ZDoom

If you have a IME active while running GZDoom, such as the Windows Japanese IME, controls for the menu can become unreliable. Pressing escape to activate the menu will frequently cause the menu to appear for a frame, and then immediately disappear the next, among other oddities. Pressing enter at the titlepic will usually result in the game instantly going into the new game menu. The console is also spotty during gameplay. I noticed this a while back, but completely forgot to post it, but watching pomu's stream using gzdoom (still active at the time of posting) reminded me since she had some issues like that while playing.

To the best of my knowledge, most other controls remain stable.

You'll have to wait for an IME user to submit a fix.
Until then, this will be put on hold.