This is by design. It auto completes with a spacebar if you explicitly start the autocomplete.
Otherwise the autocomplete feature can interfere with your typing. It happens all the time with visual studio. It completes the wrong value (because there is no correct value at that point) and then you need to go back and delete the completion.
I too would love to be able to use the spacebar as I find I’m fighting to get back the autocompleted item that was there, as I use this so much in visual studio.
I understand your reasons but am fighting this every time I use b4a
Could it maybe be an editor option to work like visual studio does?