The following line of code is causing problems when going into fullscreen mode with subwindows
src/mswin/fg_window_mswin.c:992 s |= WS_POPUP;
The popup window style causes problems on Windows 7 (haven't tested other platforms).
Specifically, if I have a window with one or more subwindows, this flag seems to cause
the main window to change it's z-order to be in front of all the subwindows. This is
a problem because then I can no longer see any of the subwindows I created. I don't know
if this is the proper way to fix this problem, but it seems to work.
I have attached a test program to illustrate the problem on windows. I have also attached a patch that might fix the problem. However, there may be a better way to solve the problem. I am not a windows programmer, so I don't have detailed knowledge about the specific style flags and what exactly they do.