When the L key is pressed the whole edit input is selected independent of whether the ctrl key is pressed. The problem is in xfce_appfinder_window_key_press_event function and particular where checking if ctrl key is pressed. The operator should be the binary AND (&) and not the boolean AND (&&).
Created attachment 3947 Fix-operator-for-event-state-bug-8122.patch
Jannis fixed this in aa65c1.