Problem:   When creating a win32-darkmode menu bar, it is ownerdrawn and one of the known problems is that it creates a white line at the bottom. My understanding is that the white line and the menubar are both part of the non-client area. Known solutions to this problem in C++ (https://github.com/notepad-plus-plus/notepad-plus-plus/blob/bab3573be708bb908b8080e3e2007ea78a7f1932/PowerEditor/src/NppDarkMode.cpp#L672) get the size, create a dark brush and fill that line with a dark b