Windows: clicking pane header does nothing, cannot assign windows

[b451c]

Description

On Windows 10, clicking the pane header does not open the context menu and windows cannot be assigned to panes. The extension loads in REAPER and the container opens, but core interaction is non-functional.

Reported by @alienmindarts on the REAPER forum.

Environment

• OS: Windows 10 x64
• REAPER: 7.x
• MaxPane: v1.5.1

Likely causes

The extension was developed and tested on macOS (arm64) using SWELL. Windows uses native Win32 API which may differ in:

1. Dialog message handling - CreateDialogIndirectParam may not route WM_LBUTTONDOWN / WM_RBUTTONDOWN to the DlgProc the same way SWELL does
2. Window enumeration - FindWindow / EnumChildWindows may return different results for REAPER's windows on Win32 vs SWELL
3. SetParent behavior - Win32 SetParent + WS_CHILD style changes may need different handling than SWELL
4. Hit testing - coordinate systems or client rect calculations may differ

Steps to reproduce

1. Install reaper_maxpane-x64.dll into REAPER UserPlugins on Windows
2. Open REAPER, run "MaxPane: Open Container"
3. Click on a pane header - nothing happens
4. Right-click on a pane header - nothing happens

Notes

This is the first runtime test on Windows. The codebase compiles cleanly on Windows via CI (MSVC/VS2022) but has never been tested at runtime. A debug build with file logging would help diagnose where messages are being lost.