One undo-block opener for the whole tree: fourteen sites route through it, and the reclaim span can no longer swallow a user's act

The drain refuses a tick inside a foreign block; applyMode wakes the reclaimer
before it opens the span.

src/shell/capture/insert.cpp

@@ -33,6 +33,7 @@
 #include "shell/panel/panel_bank_ops.h"  // bankPanelSelectedSampleIds / SourceBankId
 #include "core/capture/capture_paths.h"
 #include "shell/persist/session.h"
+#include "shell/undo/undo_block.h"
 
 #define REAPERAPI_MINIMAL
 #define REAPERAPI_WANT_CountSelectedTracks
@@ -44,8 +45,6 @@
 #define REAPERAPI_WANT_SetOnlyTrackSelected
 #define REAPERAPI_WANT_SetTrackSelected
 #define REAPERAPI_WANT_ShowConsoleMsg
-#define REAPERAPI_WANT_Undo_BeginBlock2
-#define REAPERAPI_WANT_Undo_EndBlock2
 #include "reaper_plugin_functions.h"
 
 namespace reasampler {
@@ -139,9 +138,8 @@ InsertResult runInsert(ReaSamplerSession* session, const InsertRequest& request)
     const double cursorPos = GetCursorPosition();
 
     // One undo block around the whole placement (all tracks + selection/cursor
-    // restore) so a single undo removes every item and restores prior state. Always
-    // balanced — opened before the first insert, closed after the restore.
-    Undo_BeginBlock2(nullptr);
+    // restore) so a single undo removes every item and restores prior state.
+    UndoBlock undo(nullptr);
 
     // Insert onto each selected track at the same cursor position (assumption B): per
     // track, isolate it as the only selection (A + E), reset the cursor (C is
@@ -159,11 +157,10 @@ InsertResult runInsert(ReaSamplerSession* session, const InsertRequest& request)
 
     // Label reflects count + conform choice for a clear undo history. extraflags -1 =
     // UNDO_STATE_ALL (tracks, items, envelope points, project state).
-    const std::string label =
-        "ReaSampler: insert on " + std::to_string(result.inserted) +
-        (result.inserted == 1 ? " track" : " tracks") +
-        (request.options.conform == TempoConform::None ? "" : " (conform)");
-    Undo_EndBlock2(nullptr, label.c_str(), -1);
+    undo.recordPoint("ReaSampler: insert on " + std::to_string(result.inserted) +
+                         (result.inserted == 1 ? " track" : " tracks") +
+                         (request.options.conform == TempoConform::None ? "" : " (conform)"),
+                     -1);
 
     result.status = InsertStatus::Ok;
     return result;