[Windows] After changing the UI scale, "Load Game" and "Open Game" become unresponsive

[NQNStudios]

When you change the UI scale in the main menu, the Load Game button and the Open Game option in the menubar both become unresponsive after the window resizes. (Note: the button still draws itself as pressed when clicked. It just doesn't do anything.)

It seems to only affect game loading. "Make New Party", "New Game" in the menubar, and "Start Scenario" continue to work in the changed state.

[NQNStudios]

Other things also break after the window is recreated, including "Save As". The reason is that the file browser dialogs are created in init_fileio() with mainPtr as a parent, but mainPtr is invalidated when the window changes, so calling init_fileio() again might fix this.