Disappearing Desktop Icons

I am using US English LibreOffice Writer with the current Linux Mint on a PC, with a Lenovo pivot monitor, which I normally use in portrait mode. Today I used it a bit in landscape mode and then returned to portrait (using the Display settings). When I did so, all the icons on my desktop had disappeared. I returned to landscape mode, but the desktop was still empty. The desktop contents seem to be hidden offscreen or something, since I can access them by opening the Home directory. The applications that I load into the panel are still visible.

The problem is that I keep a lot of icons (applications, directories, and files) on the desktop, and rely on them to start programs and find files. Is there some way I can check out parts of the desktop that are not visible, and shift the centering?

Not really an LO-issue, but still;

I have the same problem when changing from a dual- to single-display-setup and vice verca. My workaround is to open up System → Preferences → Monitors and change the resolution of my screen. Say, you are running 1600x1200, change to 1280x1024 and apply. Change back immediately. Icons (and windows in my case) should be there.