From GigaLem on Discord:
Quote from: GigaLem1)Open SLX editor and open both Level Arranger Window and Piece Selector Window
2)zoom in on the level till the scoll bars appear
3)Click on Steel in the Piece Window then Refocus Level window
4)Try to move the Piece or press any of the hotkey
Note: An extra step is required after (1) - add a piece to the level and select it (it can be any piece)
Confirmed that this bug exists in 2.9.2.
The problem seems to be that, when refocusing the Level Arranger Window, the scrollbar controls are eating the directional hotkeys (and, indeed, any other hotkeys). Should be a relatively straightforward fix.
Fixed in commit d55649c.