Floating windows do not respond until menu bar is reactivated

[neon-age]

When entering Borderless mode, floating windows become unfocusable and do not respond to any clicks.
Re-activating menu bar fixes this (calls Win32.DrawMenuBar(wnd)), until the next window is opened.

[neon-age]

This can be fixed by removing case WM.NCACTIVATE: in WindowProc method, but it will cause menu bar to flash for a frame during alt-tab and when windows are opened/closed :(