Avoids enum casts when it's used for reader.

Tests show that there is a ~1.5s timer that checks for the presence of WS_EX_TOPMOST and restore it
if it got removed when the timer times out. Manual tests that skip WM_TIMER handling show there is a
1.5s timer of ID 0x4242 keeps firing. The timer stops when its WM_TIMER message gets handled.

Fix Deus Ex: Game of the Year Edition missing WS_EX_TOPMOST after changing resolutions in fullscreen
mode. The application removes WS_EX_TOPMOST from its game window after entering fullscreen.

Test that there is a ~1.5s timer after entering fullscreen mode and restores WS_EX_TOPMOST if it's
missing when the timer times out.