I've got a second monitor, it stands to the left of my laptop. By default, it's displayed as the right monitor in Xfce display settings. When I swap the left and right monitors, the panel and desktop move to the second monitor even though the laptop's display is still listed as the primary. Googling suggests that this was filed as a bug some 12 years ago. Does this still not work properly in general?
UPDATE: I was able to solve this by separately configuring the panel, notifications, and desktop icons as follows:
- Panel Preferences > General > Display > Output > Primary instead of Automatic (you can also explicitly set the monitor you need)
- Desktop > Icons > Appearance > Show icons on primary display (set the checkbox)
- Notifications > General > Behavior > Show notifications on: primary display
Note that with desktop icons, it only seems to be possible to make them display on the primary monitor
or whichever monitor Xfce chooses. Similarly, the notifications can be set to display either on the primary monitor or on the monitor where the mouse pointer currently is.
The whole thing does not present an optimal experience. IMO, the panel, desktop icons, and notifications should display by default on the primary monitor but allow selecting a specific monitor instead.