Drops a false claim about ReaSampler's own editor's hInstance, corrects the real reason for registering the wndproc class against our own module, and covers isOwnModulePath's separator edge cases.
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