I regularly use my keyboard instead of mouse, to perform window actions.
in earlier versions I used to open the "window operations menu" by Alt-F3 -> Move (today it's "more actions" -> "move"), then I used to press left/right/up/down arrows (sometimes accompanied by Ctrl or Alt, to change "speed"), and the window moved to the desired direction. pressing Enter or Esc completed the action and exited the mode.

now, this seems not to work well anymore:
- when the window runs Okular (a kde app), the window indeed moves, but the keys are passed to the app as well, turning pages forwards and backwards.
- when the window runs pqiv or lxterm or firefox (non-kde apps), the window doesn't even move, yet all keys are input to the app.

still the mode works well if I only use the mouse (and it's even usefull in some edge cases, i.e. when window opens so that its top bar is outside the screen).
but I miss the old behavior, where I could use plain keyboard for the action.

what's wrong?