S17: drag_out InstrumentDrop gesture + instrument_drop blob reusing the instrument's own serializer; bank_panel FX hover-track + add-VST/vst_chunk inject. S13 relay deferred (read-only bridge) — editor shows drop affordance.
Pure drag_out (gesture boundary + path-list assembly) + Windows OLE CF_HDROP / SWELL file-list shell; bank_panel hands off when a dragged selection leaves the client area. COPY-ONLY mask; internal drag intact.