Close the bridged-process hole in the drag-out hand-off gate

OsHandoff now needs the window-ownership proof AND a hit-test that named
nothing, so a bridged plugin's UI can't read as off-REAPER.

src/core/ui/CLAUDE.md

@@ -90,8 +90,12 @@ L7 sub-pass, 2026-07-27):
   REAPER entirely is the one irreversible transition, because the OS hand-off goes
   modal — so it must be PROVEN (a window-ownership test in the shell), never inferred
   from a hit-test token REAPER could not name; an unrecognised surface *inside* REAPER
-  refuses. A first-move class lock and a drag-lifetime "cannot hand off" latch both
-  existed here and were removed — do not reintroduce either.
+  refuses. That proof is necessary but NOT sufficient: a plugin bridged into
+  `reaper_host*.exe` fails the process test while still being REAPER's own UI, so the
+  hand-off additionally requires REAPER's hit-test to have named nothing — a recognised
+  token can only ever veto the hand-off, never produce one. A first-move class lock and
+  a drag-lifetime "cannot hand off" latch both existed here and were removed — do not
+  reintroduce either.
 
 ## Modules
 
@@ -99,7 +103,7 @@ L7 sub-pass, 2026-07-27):
 - `bank_grid` — REAPER-free grid layout, selection, keyboard-nav, and thumbnail-cache-key logic for the docked bank panel.
 - `tab_strip` — REAPER-free scrollable tab-strip layout + hit-test for the named-banks strip.
 - `prune_button` — pure layout/hit-test for the `bank_panel` footer Prune button.
-- `drag_out` — the pure drag-out gesture law plus path-list assembly. Owns the `ReaperSurface` vocabulary (TrackPanel / FxSurface / FxEmbed / Arrange / Other — `core/wire/instrument_drop` classifies REAPER's info token INTO it; there is deliberately no off-REAPER member, since no token can carry that fact), `decideDropClass` (surface × single-vs-multi payload → Internal / InstrumentDrop / ArrangeInsert / Refuse / OsHandoff / None), and `cueForDropClass`. `OsHandoff` is reachable ONLY through `DropContext::pointerOffHost`, a positive window-ownership proof the shell owes the law (`drag_out_win::pointerOverHostWindow`), gated ahead of the surface switch — so no reading of REAPER's hit-test can give a live drag away to OLE. **No `DropClass` means "nothing happens"**: a surface with no defined outcome for the payload resolves to `Refuse`, which the shell shows as a cursor, so "no silent no-op release" is a property of the enumeration rather than of any call site.
+- `drag_out` — the pure drag-out gesture law plus path-list assembly. Owns the `ReaperSurface` vocabulary (TrackPanel / FxSurface / FxEmbed / Arrange / Other — `core/wire/instrument_drop` classifies REAPER's info token INTO it; there is deliberately no off-REAPER member, since no token can carry that fact), `decideDropClass` (surface × single-vs-multi payload → Internal / InstrumentDrop / ArrangeInsert / Refuse / OsHandoff / None), and `cueForDropClass`. `OsHandoff` is reachable ONLY through `DropContext::pointerOffHost` — a positive window-ownership proof the shell owes the law (`drag_out_win::pointerOverHostWindow`) — AND only where REAPER's own hit-test named nothing (`Other`, no track), gated ahead of the surface switch, so neither evidence source can give a live drag away to OLE on its own. **No `DropClass` means "nothing happens"**: a surface with no defined outcome for the payload resolves to `Refuse`, which the shell shows as a cursor, so "no silent no-op release" is a property of the enumeration rather than of any call site.
 - `theme` — pure palette module: role→color mapping, REAPER-grey neutral ladder + the pastel accent system, the keyboard strip's spectral ramp, WCAG contrast-floor helpers + `compositeOver` (the effective color of a translucent fill, so alpha overlays are testable). Only the ramp's MID stop is its own constant; lo/hi are still aliases of `accent/primary`/`accent/tertiary`, so a categorical accent move CAN still reorder the ramp — `testSpectralRampLuminanceIsMonotonic` is the build-time catch, not the structure.
 - `component_geometry` — pure button/slider/list-row geometry + hover hit-test helpers.
 - `action_bar` — pure task-grouped action-bar layout/hit-test: clusters (Capture / Placement / Maintenance / Tagging / Switching).

src/core/ui/drag_out.cpp

@@ -24,10 +24,16 @@ DropClass decideDropClass(int px, int py, const PanelClientRect& client,
     if (!ctx.drag.dragging || !ctx.drag.hasArmedSamples) return DropClass::None;
     if (insideClient(px, py, client)) return DropClass::Internal;
 
-    // The hand-off gate sits AHEAD of the surface switch and is the only route to OsHandoff, so
-    // no reading of REAPER's hit-test — recognised, unrecognised, or empty — can reach the modal
-    // OLE loop while the pointer is still over a host window.
-    if (ctx.pointerOffHost) return DropClass::OsHandoff;
+    // The ONE route to OsHandoff, ahead of the surface switch, and it needs BOTH halves. The
+    // shell's ownership proof alone is not sufficient: REAPER runs a bridged plugin's UI in a
+    // separate process, so a window failing that test can still be REAPER's own UI. A recognised
+    // token therefore VETOES the hand-off instead of producing one — a veto can only move the
+    // answer toward staying inside REAPER, so pointerOffHost remains the only member whose true
+    // value can reach OLE. An off-host point REAPER DID name falls through to that surface's own
+    // outcome below: over a bridged FX window that is the instrument drop, as it is for a native
+    // one.
+    if (ctx.pointerOffHost && ctx.surface == ReaperSurface::Other && !ctx.haveTrack)
+        return DropClass::OsHandoff;
 
     switch (ctx.surface) {
         case ReaperSurface::TrackPanel:

src/core/ui/drag_out.h

@@ -6,10 +6,9 @@
 //
 // THE LAW: the class is resolved from what is under the cursor on EVERY move; every transition
 // is reversible until release or until the pointer leaves REAPER entirely; the OS hand-off is
-// reserved for leaving REAPER — which the shell must PROVE (DropContext::pointerOffHost), never
-// infer from a hit-test token it could not name — and every REAPER-internal target executes
-// natively on release. Do not reintroduce a first-move class lock or a drag-lifetime "blocked"
-// latch.
+// reserved for leaving REAPER (DropContext::pointerOffHost owns what proves that) and every
+// REAPER-internal target executes natively on release. Do not reintroduce a first-move class
+// lock or a drag-lifetime "blocked" latch.
 //
 // Path-list assembly: turns armed sample ids into the absolute path list an OS drop carries
 // (Windows CF_HDROP / macOS file-list pasteboard) — set algebra only; the shell resolves each id
@@ -34,10 +33,8 @@ struct DragState {
 };
 
 // What REAPER reports under the pointer, reduced to the surfaces the law distinguishes.
-// Produced from GetThingFromPoint's info token by wire::classifyReaperSurface. There is
-// deliberately NO off-REAPER member: this vocabulary describes what REAPER's own hit-test
-// named, and "the pointer left REAPER" is a window-ownership fact no token can carry —
-// it enters through DropContext::pointerOffHost instead.
+// Produced from GetThingFromPoint's info token by wire::classifyReaperSurface. No off-REAPER
+// member: that fact enters through DropContext::pointerOffHost, which owns the reasoning.
 enum class ReaperSurface {
     TrackPanel,  // TCP/MCP, ANY sub-element: the WHOLE panel is the instrument hotspot
     FxSurface,   // fx_* — the FX chain and floating-FX windows
@@ -68,12 +65,14 @@ struct DropContext {
     bool singlePayload = false;  // payload holds EXACTLY one capture (arms InstrumentDrop)
     ReaperSurface surface = ReaperSurface::Other;  // only read outside the client rect
     bool haveTrack = false;      // GetThingFromPoint returned a non-null MediaTrack*
-    // The ONE gate on the irreversible OS hand-off, and the only member whose true value can
-    // produce it. It is a POSITIVE proof the shell owes the law — a window-ownership test
-    // (drag_out_win::pointerOverHostWindow), not "the hit-test named nothing I recognise",
-    // which is equally true of the transport, the toolbar and the docker chrome. Defaults
-    // false so an unset context stays inside REAPER: the failure mode of forgetting to
-    // resolve it must be a refusal, never a drag given away to OLE.
+    // THE ONE HOME for the hand-off's evidence rule. This is the only member whose true value
+    // can reach the irreversible OS hand-off, and it is a POSITIVE proof the shell owes the law
+    // — a window-ownership test (drag_out_win::pointerOverHostWindow), never "the hit-test named
+    // nothing I recognise", which is equally true of the transport, the toolbar and the docker
+    // chrome; reading an unnamed token as an exit is what handed live drags to OLE mid-gesture.
+    // Defaults false so an unset context stays inside REAPER: the failure mode of forgetting to
+    // resolve it must be a refusal, never a drag given away to OLE. NECESSARY but not sufficient
+    // — decideDropClass's gate carries the second half and why it needs one.
     bool pointerOffHost = false;
 };
 

src/core/wire/CLAUDE.md

@@ -81,7 +81,7 @@ This directory owns two cross-artifact contracts specifically:
 - `reasampler_uid.h` — SDK-free header owning the FOREVER-FROZEN VST3 class-UID integer macros (stable + beta pairs, `REASAMPLER_PROC_UID_*` / `REASAMPLER_PROC_UID_BETA_*`) and the `REASAMPLER_ACTIVE_UID_*` channel-selector macros. Split out of `reasampler_vst.h` so the pure extension side (`instrument_drop`) can derive the `.vstpreset` class-ID hex string without pulling in the VST3 SDK. Both `reasampler_vst.h` (runtime `FUID`) and `instrument_drop` (preset hex string) source from this single header — the binary identity and the preset-file identity cannot diverge.
 - `assignment_request` — pure ingest-assign wire: typed request record carrying the drop payload from the `ingest` shell through to the VST3 bridge.
 - `bake_wire` — the resample bake's request/outcome pair on ONE per-instance key (`rsbake_<guid>`): the instrument writes a `BakeRequest`, invokes the extension's action synchronously, and reads the extension's `BakeOutcome` back over the same key inside that one call. Not a handshake — a call and a return, and it must not grow a claim protocol. Also the ONE home of the bake action's command-id suffix and of the leading underscore `NamedCommandLookup` needs but `rec->Register("command_id", …)` does not, so both artifacts name one action. `BakeStatus` values are WIRE INTEGERS: never renumber, only append, and an unrecognized value decodes as `Failed` rather than as the numeric default `Ok`. It owns BOTH ends' reading of that key, since the key's contents are the only evidence either side gets: `classifyBakeAnswer` (instrument side — six kinds, of which `Unanswered`, the request still sitting there untouched, separates "nothing wrote an outcome over our key" from a refusal — it does NOT identify a landing that never ran, since a skipped key and a rejected answer-write look identical from here) and `classifyBakeScan` + `kMaxRequestAgeSeconds` (extension side — the per-key Land / RefuseWrongProject / ClearStale / IgnoreUnreadable / IgnoreNotARequest verdict over every open tab, stated without a REAPER type so the multi-tab matrix is unit-provable). `BakeScanTally` + `describeBakeScan` + `describeBakeKey` are that same reading counted and spoken — the rationale lives at the types. **The report's absence is NOT evidence the landing never ran**, and no sentence either artifact prints may say it is: `answered` is pass-wide and counts a QUEUED write, so a pass can answer some other key while skipping ours, or have our own answer's `SetProjExtState` rejected. The summary is therefore silent only when the pass answered somebody, left no key unanswered, and every answer was READ BACK from its own key; `describeBakeKey` prints one line per enumerated key regardless, which is the only thing that names WHICH key — the counts cannot. The read-back verdict behind `BakeWriteProof` is `ext_state_read.h`'s `extStateWriteLanded`, above. `bakeLandingAfterPersist` is the ONE route to a `Banked` landing: every `Land` verdict is assigned `Unpersisted` and passed through it, so no shell path — a dedup hit least of all, since its target may be an entry the same pass just added — can claim the word without the pass's persist having reported success. What `Banked` claims is exactly that `persisted` input — a saved project was active and the bank write was issued — and the enum comment is that claim's one home.
-- `instrument_drop` — pure FX-drop payload builder: constructs a Steinberg-format `.vstpreset` image (channel-active class ID + the instrument's own component state, capture pre-selected) the shell applies via `TrackFX_SetPreset`; owns `classifyReaperSurface`, the prefix classifier mapping a `GetThingFromPoint` info token onto `core/ui/drag_out`'s `ReaperSurface`. Classifier ordering is load-bearing: the embed strip is matched before the `tcp`/`mcp` panel family, which claims the WHOLE track panel rather than just its FX sub-elements. An empty token is `Other`, never an off-REAPER verdict — the SDK documents no off-REAPER return, so the toolbar/transport/docker chrome all report nothing REAPER names. All-or-nothing contract — caller rolls back via `TrackFX_Delete` on any failure.
+- `instrument_drop` — pure FX-drop payload builder: constructs a Steinberg-format `.vstpreset` image (channel-active class ID + the instrument's own component state, capture pre-selected) the shell applies via `TrackFX_SetPreset`; owns `classifyReaperSurface`, the prefix classifier mapping a `GetThingFromPoint` info token onto `core/ui/drag_out`'s `ReaperSurface`. Classifier ordering is load-bearing: the embed strip is matched before the `tcp`/`mcp` panel family, which claims the WHOLE track panel rather than just its FX sub-elements. An empty token is `Other`, never an off-REAPER verdict (`core/ui/CLAUDE.md` owns that rule). All-or-nothing contract — caller rolls back via `TrackFX_Delete` on any failure.
 - `sample_usage` — instance-usage wire: `UsageRecord`, `planUsagePublish` (fresh/heal/clean-replace/union/remint publish plan), `foldUsageRecords`/`usageHeldPaths` (liveness fold — protect-all when records exist but no instance is live; abort→protect-all on unreadable record; `counted` carries key-attributed live records), `identityMatches` (ReaSampler 9000 FX identity). REAPER-free, unit-tested. The mirror of `assignment_request` on the instrument→extension direction: the wire format and the two safety-critical decisions (what to write on publish, which records count at prune time) are pure so they are provable without a DAW. It lives here because it is a *wire format* with an instrument-side writer; the fold's output is consumed by `core/tracking`'s authority, which owns every consumer-facing decision built on it.
 
 ## Gotchas

src/core/wire/instrument_drop.h

@@ -67,11 +67,8 @@ std::vector<std::uint8_t> buildInstrumentDropPreset(const std::string& sampleId)
 //       why such a drop landed nowhere.
 //   "arrange*"                      -> Arrange.
 //   anything else, "" INCLUDED      -> Other. A surface we cannot name: refuse
-//       visibly, never guess an outcome. An empty token is NOT evidence the pointer
-//       left REAPER — the SDK documents no off-REAPER return at all, and the transport,
-//       toolbar, menu bar and docker chrome all report nothing REAPER names. Reading it
-//       as "off REAPER" is what handed live drags to OLE mid-gesture; whether the
-//       pointer left is a window-ownership fact, resolved in the shell.
+//       visibly, never guess an outcome. An empty token is NOT evidence the pointer left
+//       REAPER — see ui::DropContext::pointerOffHost for why that rule exists.
 // The exact live token is DAW-only — confirm via
 // reaper.GetThingFromPoint(reaper.GetMousePosition()) in ReaScript if unsure.
 ui::ReaperSurface classifyReaperSurface(const std::string& info);

src/shell/actions/CLAUDE.md

@@ -41,8 +41,8 @@ is owned by other directories and only skinned here.
 
 - `shell/actions` (`action_registry` / `design_view_actions` / `bank_actions` / `prune_action`) — the bindable action families, all routed via the `command_id`/`gaccel`/`hookcommand` contract. `action_registry` owns the shared registration plumbing (interned channel-qualified id strings; register and mirror-unregister present the identical pointer) **and the Q-W6 registration TABLE**: `main.cpp`'s own family (capture scopes, panel toggle, insert, batch, realtime, recapture, version) is one `ActionTableRow` array — suffix, phrase, flat function-pointer handler — that registration, hookcommand dispatch, and the unload mirror-unregister all iterate, so adding an action touches the table only (OCP). Bank mutations flow through the promptless `shell/bank_ops` verbs (`bankOp*` + `persistBankOp`, taking `ReaSamplerSession&`), which the panel menus and `bank_actions` consume as thin UX skins. **Every bank index verb wraps its mutation in a batched REAPER undo point (`Undo_BeginBlock2`/`EndBlock2`, `UNDO_STATE_MISCCFG`) so one bank operation is one Ctrl-Z.** The prune action (`prune_action`, `BANK_PRUNE_FOLDER`) is **the ONLY file-deletion action in the system**; it opens no undo point (file deletion is not REAPER-undoable). `BANK_PRUNE_FOLDER` halts on `blockedByTracking` and prints each blocker that fired, with recovery instructions.
 - `package_export_action` — the "export bank as package" skin: survey and report first, confirm what is absent (and, separately, a destination being replaced), pick a destination, write. Every prompt in the flow lives here so `shell/package/export_bank` stays promptless. Read-only against the project — it holds the session by `const&`, so no ext-state write, generation bump or undo point is reachable. Registration rides `main.cpp`'s action table (`EXPORT_BANK_PACKAGE`); the panel's tab menu is the second skin over the same body.
-- `drag_out_win` — the host/OS boundary of drag-out: Windows OLE `DoDragDrop`/`CF_HDROP`, copy-only (`DROPEFFECT_MOVE` not offered); macOS/Linux via `SWELL_InitiateDragDropOfFileList`. Also owns `pointerOverHostWindow`, the window-ownership test behind `ui::DropContext::pointerOffHost` — process identity on Windows (`WindowFromPoint` + `GetWindowThreadProcessId`), non-null `WindowFromPoint` under SWELL, whose window list is already this-process-only.
-- `instrument_drop_win` — instrument-drop shell: `probeDropTarget` resolves a screen point to a track + a `ReaperSurface` (via the pure `wire::classifyReaperSurface`, whose token rules `core/wire/CLAUDE.md` owns) — it answers only what REAPER named, never whether the pointer is still in REAPER, which is `drag_out_win`'s — and the drop half adds a ReaSampler 9000 instance and applies the dragged capture's state via a transient `.vstpreset` + `TrackFX_SetPreset` (the former `TrackFX_SetNamedConfigParm` "vst_chunk" write was silently unappliable for VST3). Exposes `loadInstrumentOntoTrack` (inner half, no own undo block) and `performInstrumentDrop` (wraps in its own undo block). **Never captures, never writes the bank, never inserts a timeline item.**
+- `drag_out_win` — the host/OS boundary of drag-out: Windows OLE `DoDragDrop`/`CF_HDROP`, copy-only (`DROPEFFECT_MOVE` not offered); macOS/Linux via `SWELL_InitiateDragDropOfFileList`. Also owns `pointerOverHostWindow`, the window-ownership test behind `ui::DropContext::pointerOffHost` (`core/ui/CLAUDE.md` owns the hand-off rule it feeds) — process identity on Windows (`WindowFromPoint` + `GetWindowThreadProcessId`), non-null `WindowFromPoint` under SWELL, whose window list is already this-process-only. Its shipped exception: a plugin bridged into `reaper_host*.exe` reports off-host though the pointer never left REAPER.
+- `instrument_drop_win` — instrument-drop shell: `probeDropTarget` resolves a screen point to a track + a `ReaperSurface` (via the pure `wire::classifyReaperSurface`, whose token rules `core/wire/CLAUDE.md` owns) — it answers only what REAPER named, never whether the pointer is still in REAPER — and the drop half adds a ReaSampler 9000 instance and applies the dragged capture's state via a transient `.vstpreset` + `TrackFX_SetPreset` (the former `TrackFX_SetNamedConfigParm` "vst_chunk" write was silently unappliable for VST3). Exposes `loadInstrumentOntoTrack` (inner half, no own undo block) and `performInstrumentDrop` (wraps in its own undo block). **Never captures, never writes the bank, never inserts a timeline item.**
 - `arrange_drop_win` — the drag-out gesture's arrange outcome: `arrangeTimeAtScreenX` (pointer column → time via `GetSet_ArrangeView2`'s one-pixel-span reading — inferred, not SDK-documented) and `performArrangeDrop` (snap the drop time, then one `InsertMedia` per capture on the pointer's track — assumed, not confirmed, to land end-to-end via REAPER's own cursor advance — in ONE undo block, counting only InsertMedia's reported successes, with the caller's track selection and edit cursor restored). The one timeline-placing shell here, per the invariant above; it never captures and never writes the bank.
 - `package_import_action` — the bindable / bank-menu / file-drop skin over `shell/package`'s `importBankPackage`. Owns the **ledger gate**, which runs BEFORE the file picker (a refusal must not cost the user a file choice) and is keyed on the session's `LedgerStatus` alone — never on `PruneReport::blockedByTracking`, whose undecodable-`rsusage_*` arm governs deletion-time protection and would refuse an import that only writes birth records. Builds and shows every message the import produces, but the ledger-refusal body itself is `core/package::ledgerRefusalMessage` — a pure fold this TU only supplies the channel-correct namespace to — so the wording is assertable without a DAW. `doImportBankPackage`/`doImportBankPackageFile` return the minted bank id on a landed import (empty otherwise) so a caller can focus it; the verb itself is promptless.
 - `ingest` — ingest-through-the-bank shell on the EXTENSION side: three surfaces — (1) arrange capture→bank→assign (bindable action), (2) Media-Explorer import→bank→instrument on the selected track, (3) file drop onto the bank panel→bank only. Only surface (1) writes the `assignment_request` ext-state wire. **ingest NEVER inserts a timeline item.** Surface (2)'s action is the one in this directory published into a NON-main action section (Media Explorer) as well as Main — two ids, one handler, two dispatch hooks; see root `CLAUDE.md` §"REAPER extension contract" for the mechanism.

src/shell/actions/drag_out_win.cpp

@@ -247,14 +247,18 @@ bool canInitiateDragOut(const std::vector<std::string>& absolutePaths) {
 bool pointerOverHostWindow(int screenX, int screenY) {
     // Process identity, not window identity: REAPER's arrange, its floating FX and VST editor
     // windows, its menus and its docker chrome are separate top-level HWNDs with no common
-    // ancestor, so no GetAncestor/GetParent walk reaches them all — but every one of them is
-    // created by the process this extension is loaded into.
+    // ancestor, so no GetAncestor/GetParent walk reaches them all — but they are windows of the
+    // process this extension is loaded into, bar the bridged-plugin case the header names.
     // Mouse capture does not affect WindowFromPoint: it hit-tests the desktop window tree, not
-    // input routing. It does skip hidden and DISABLED windows, so a REAPER window disabled
-    // behind a modal dialog could fall through to whatever sits beneath — no such dialog can be
-    // up while our panel holds capture for a drag.
+    // input routing. It does skip hidden and DISABLED windows, so a REAPER window disabled behind
+    // a modal dialog raised mid-drag (a REAPER timer or another extension can raise one — capture
+    // is not a modality lock) would fall through to whatever sits beneath and read as off-host.
+    // Accepted, unverified: not reproduced, and nothing here was checked against REAPER's own
+    // dialog behavior.
     const POINT pt{screenX, screenY};
     const HWND hwnd = WindowFromPoint(pt);
+    // Not an unknown resolved toward hand-off: a null return is the desktop tree stating there is
+    // no window at that point at all, which is a determinate "no host window here".
     if (!hwnd) return false;
     DWORD pid = 0;
     GetWindowThreadProcessId(hwnd, &pid);

src/shell/actions/drag_out_win.h

@@ -33,11 +33,14 @@ bool initiateDragOut(HWND__* panelHwnd, const std::vector<std::string>& absolute
 // probe HGLOBAL immediately; SWELL exposes no probe, so macOS/Linux reduces to the non-empty check.
 bool canInitiateDragOut(const std::vector<std::string>& absolutePaths);
 
-// True iff a window belonging to the host (REAPER) process sits under the screen point —
-// the POSITIVE proof ui::DropContext::pointerOffHost is the negation of. Every REAPER
-// surface qualifies whether or not GetThingFromPoint can name it: the arrange, a TCP, a
-// floating FX or VST editor window, the transport, the toolbar, a menu, the docker chrome
-// and our own panel are all windows of this process, because the extension runs inside it.
+// True iff a window belonging to the host (REAPER) process sits under the screen point — the
+// POSITIVE proof ui::DropContext::pointerOffHost is the negation of (that member owns the
+// evidence rule). Nearly every REAPER surface qualifies whether or not GetThingFromPoint can
+// name it, because the extension runs inside that process.
+// The exception, and it ships: a plugin set to "Run as separate/dedicated process" draws its
+// UI out of reaper_host32/64.exe, and WindowFromPoint descends to the deepest child — so this
+// reports false over a bridged plugin's editor although the pointer never left REAPER. The
+// law's hand-off gate absorbs that by also requiring REAPER's own hit-test to name nothing.
 // Side-effect-free; safe on every mouse-move.
 bool pointerOverHostWindow(int screenX, int screenY);
 

src/shell/actions/instrument_drop_win.h

@@ -35,8 +35,8 @@ struct DropProbe {
 // Wraps GetThingFromPoint: its track comes back as-is, its info string goes to the pure
 // wire::classifyReaperSurface. Cheap enough to run on every mouse-move, but the panel
 // evaluates it only OUTSIDE its own client rect — the internal drag never pays for it.
-// It reports only what REAPER named; whether the pointer is still inside REAPER at all is
-// drag_out_win::pointerOverHostWindow's, and no surface reported here implies an exit.
+// Reports only what REAPER named; no output here implies an exit (ui::DropContext::
+// pointerOffHost owns that rule).
 DropProbe probeDropTarget(int screenX, int screenY);
 
 // Adds a fresh ReaSampler 9000 instance to `track` and applies `presetBytes` as its

src/shell/panel/panel_drag.cpp

@@ -199,11 +199,9 @@ LiveDrop resolveLiveDrop(int x, int y) {
         const DropProbe probe = probeDropTarget(sp.x, sp.y);
         ctx.surface = probe.surface;
         ctx.haveTrack = probe.track != nullptr;
-        // Two independent probes because they answer two independent questions: REAPER's
-        // hit-test names the surface, window ownership decides whether we are still in REAPER
-        // at all. The SDK hit-test cannot answer the second — GetThingFromPoint documents no
-        // off-REAPER return, so its silence over the transport or the toolbar used to read as
-        // "the user left" and gave the live drag away to OLE.
+        // Two probes because they answer two independent questions: what REAPER named, and
+        // whether we are still inside REAPER at all. The law's hand-off gate reads both — see
+        // ui::DropContext::pointerOffHost.
         ctx.pointerOffHost = !pointerOverHostWindow(sp.x, sp.y);
         out.track = probe.track;
         out.screenX = sp.x;
@@ -249,6 +247,10 @@ void handOffToOs() {
     invalidatePanel();
 
     initiateDragOut(g_panel.hwnd, paths);  // COPY-ONLY; blocking on Windows
+
+    // The drag state was reset above, so the WM_LBUTTONUP that ends the modal loop takes
+    // onLBtnUp's not-dragging branch and never restores the arrow — do it here instead.
+    SetCursor(LoadCursor(nullptr, IDC_ARROW));
 }
 
 // Resolves the topmost INTERACTIVE element under client (x, y) for hover feedback,

tests/test_drag_out.cpp

@@ -41,7 +41,8 @@ static DropContext ctx(ReaperSurface surface, bool single = true, bool haveTrack
 }
 
 // The same drag with the shell's positive off-REAPER proof set. `surface` is whatever the SDK
-// hit-test last reported; the point of the gate is that it no longer matters.
+// hit-test reported at that point — it still matters: the hand-off needs REAPER to have named
+// nothing too, so the defaults here (Other, no track) are the only combination that hands off.
 static DropContext offHost(ReaperSurface surface = ReaperSurface::Other, bool single = true,
                            bool haveTrack = false) {
     DropContext c = ctx(surface, single, haveTrack);
@@ -212,20 +213,57 @@ static void testNoInReaperCombinationCanHandOff() {
     }
 }
 
-// The converse: once the shell has PROVEN the pointer left, the hand-off does not depend on what
-// the last hit-test happened to say or on whether a track was resolved — the gate sits ahead of
-// the surface switch, so a stale surface reading cannot suppress a genuine exit.
-static void testOffHostHandsOffWhateverTheSurfaceSaid() {
+// The converse, stated as the gate's exact shape: with the ownership proof set, the hand-off
+// happens EXACTLY on the cells where REAPER's hit-test also named nothing — no surface, no track.
+// Both directions in one loop, so neither half can be weakened without a failure: a gate that
+// dropped the token condition fails on the named cells, one that over-tightened fails on Other.
+static void testOffHostHandsOffOnlyWhereReaperNamedNothing() {
     for (ReaperSurface s : kAllSurfaces) {
         for (bool single : {true, false}) {
             for (bool haveTrack : {true, false}) {
-                CHECK(decideDropClass(kOutX, kOutY, kPanel, offHost(s, single, haveTrack)) ==
-                      DropClass::OsHandoff);
+                const bool namedNothing = (s == ReaperSurface::Other) && !haveTrack;
+                const DropClass c =
+                    decideDropClass(kOutX, kOutY, kPanel, offHost(s, single, haveTrack));
+                CHECK((c == DropClass::OsHandoff) == namedNothing);
             }
         }
     }
 }
 
+// The shipped exception the token condition exists for: REAPER runs a bridged plugin's UI in
+// reaper_host*.exe, so the window-ownership test reports off-host over a floating bridged FX
+// editor even though the pointer never left REAPER. There the recognised token vetoes the
+// hand-off and the surface's own REAPER-internal outcome stands — identical to the native case.
+static void testOffHostOverANamedSurfaceKeepsTheReaperOutcome() {
+    CHECK(decideDropClass(kOutX, kOutY, kPanel, offHost(ReaperSurface::FxSurface, true, true)) ==
+          DropClass::InstrumentDrop);
+    CHECK(decideDropClass(kOutX, kOutY, kPanel, offHost(ReaperSurface::TrackPanel, true, true)) ==
+          DropClass::InstrumentDrop);
+    CHECK(decideDropClass(kOutX, kOutY, kPanel, offHost(ReaperSurface::Arrange, true, true)) ==
+          DropClass::ArrangeInsert);
+    CHECK(decideDropClass(kOutX, kOutY, kPanel, offHost(ReaperSurface::FxEmbed, true, true)) ==
+          DropClass::Refuse);
+
+    // And not just for those four spot values: over every named cell the ownership proof changes
+    // nothing at all, which is what "a veto can only move the answer toward staying in REAPER"
+    // means operationally.
+    for (ReaperSurface s : kAllSurfaces) {
+        if (s == ReaperSurface::Other) continue;  // the one surface the gate can hand off from
+        for (bool single : {true, false}) {
+            for (bool haveTrack : {true, false}) {
+                CHECK(decideDropClass(kOutX, kOutY, kPanel, offHost(s, single, haveTrack)) ==
+                      decideDropClass(kOutX, kOutY, kPanel, ctx(s, single, haveTrack)));
+            }
+        }
+    }
+    // Same equality on the remaining named cell: Other WITH a track is a surface REAPER did
+    // attribute, so it refuses off-host exactly as it does on-host.
+    for (bool single : {true, false}) {
+        CHECK(decideDropClass(kOutX, kOutY, kPanel,
+                              offHost(ReaperSurface::Other, single, true)) == DropClass::Refuse);
+    }
+}
+
 // --- Not-a-drag ----------------------------------------------------------------
 
 // No armed samples, or not dragging -> None regardless of position or surface.
@@ -471,7 +509,8 @@ int main() {
 
     testNullTrackWithSurfaceRefuses();
     testNoInReaperCombinationCanHandOff();
-    testOffHostHandsOffWhateverTheSurfaceSaid();
+    testOffHostHandsOffOnlyWhereReaperNamedNothing();
+    testOffHostOverANamedSurfaceKeepsTheReaperOutcome();
     testNoDragOrNoSamplesIsNone();
 
     testClassTransitionsAreReversible();

tests/test_instrument_drop.cpp

@@ -248,20 +248,15 @@ static void testUnnamedReaperSurfacesAreOther() {
     CHECK(surfaceFor("something_reaper_adds_in_2030") == ReaperSurface::Other);
 }
 
-// An empty info string is Other, NOT an off-REAPER verdict. GetThingFromPoint documents no
-// off-REAPER return at all, so its silence over the transport, the toolbar or the docker chrome
-// says only "nothing I name" — reading it as "the user left REAPER" is what handed live drags to
-// OLE mid-gesture. Whether the pointer left REAPER is a window-ownership fact the shell proves
-// separately (drag_out_win::pointerOverHostWindow) and feeds to the law as
-// DropContext::pointerOffHost; no classifier output can produce a hand-off on its own.
+// An empty info string is Other, NOT an off-REAPER verdict — ui::DropContext::pointerOffHost
+// owns why.
 static void testEmptyInfoIsOtherNotOffReaper() {
     CHECK(surfaceFor("") == ReaperSurface::Other);
 }
 
-// There is deliberately no second empty-info case: track presence stopped being an input to the
-// classifier when the off-REAPER verdict left the vocabulary. "No classifier output can trigger a
-// hand-off" is now structural (no such member exists; test_drag_out's static_assert pins the
-// member count) rather than something a per-token loop could falsify.
+// There is deliberately no second empty-info case: track presence is not an input to the
+// classifier, and "no classifier output alone can trigger a hand-off" is structural (no such
+// member exists) rather than something a per-token loop could falsify.
 
 // Do not reintroduce a per-surface "capture carries" loop test: buildInstrumentDropPreset takes
 // only sampleId (proven by testPresetRoundTripsThroughInstrumentReader), and per-surface