There is a curious bug when I try to open the "Shell..." sub-menu only using the keyboard (not the mouse) in the "File Browser" window.
When I open the context menu for a file with the dedicated key for that on the keyboard and move the selection to the "Shell..." item at the bottom, the sub-menu there does never open. Neither the "enter" key nor the "Cursor right" key open that sub menu. The other sub-menus (like "Sort") work fine with the keyboard and can be opened.

I can open the Shell menu there with the mouse, but only if I have opened the whole context menu with the mouse.
This bug is also present in PLSQL Dev 14.