Game freezes when pressing Alt with WindowedMode = 2

[ArtyIF]

When I press Alt (which I binded to Speedbreaker) when I set the game to run in bordered window the game freezes until I press Alt again. This might be because Windows is trying to open a non-existent or invisible menu bar, which makes the game lose focus and freeze until this bar is closed by pressing Alt again.

[ArtyIF]

Research shows that pressing Alt sends a WM_SYSCOMMAND message with wParam being SC_KEYMENU (https://stackoverflow.com/questions/9627379/how-to-disable-normal-behaviour-of-alt-key). I don't know how to use Win32 windows and messages and stuff though so I can't really fix it myself.