Sometimes the panel grabber is too small to be clicked especially if you accidentally create a panel.
Panels DO NOT I repeat DO NOT always respond to having adjacent panels drug over them to close them especially if there were very small (see 1)
WHY CAN’T YOU JUST RIGHT CLICK THE GRABBER TO CLOSE THE PANEL? Are the developers intentionally trying to make the UI as infuriating as possible?
RMB on the panel divider to join adjacent areas