Key presses do not depress when emulator loses focus (Alt+Tab)

[ztronzo]

Alt-Tabbing out of FS-UAE would still be sending the keystrokes Alt and Tab as pressed down, even when the emulator loses focus..
This may cause strange effects when focusing back to the emulator (example: Workbench software, tab selectable menus, CLI etc.)

as a potential workaround, I used:
keyboard_key_alt_tab=action_none

So when both keys are pressed at once, they are ignored in the emulator, but they are always performed on the host OS to toggle between apps.