part selection closing directly after choosing part

Hi, A very annoying thing : before the 5.3.x updates everything was fine.

then the update came.

now , everytime i select a part in the part selector , it doesn't stay open. Normally i could choose another part directly after choosing/changina a previous part. now the whole selector resets itself after clicking at something. (which is very disturbing as a config dev modder thingy) .

something else about the selector ; sometimes when you click on '+' in the selector , the list doesnt...

part selection closing directly after choosing part