When using the up/down buttons in library path/browsing path list dialog, the selection bar vanishes from the listbox. Since Delphi 10.4 hides the focus rectangle from the Listbox, you can no longer visualy identify which item is currently selected and will be moved by clicking the buttons. This is mainly a bug in the Delphi IDE, but can be fixed in GExperts with a few lines in TSearchPathEnhancer; see attached patch.
patch applied in revision #3320