Panel drag no longer misfires on SWELL's always-zero wParam; stable/beta VST editors register distinct window classes against their own module instead of colliding on REAPER's; own-module basename matching moves to a tested pure helper.
A dragged bank card over our own instrument's editor was OLE-dropping like a third-party plugin. Classify our channel's own .vst3 module as Instrument, not Plugin, so it keeps the normal instrument-drop outcome.
A code-ownership proof (window class procedure's module, via the pure window_origin) plus REAPER's FX-surface token routes a plugin editor to OLE; FX chrome keeps the instrument drop. The OLE loop re-asks the law each turn, so passing a plugin editor stays reversible.
daniel