As you can see in the image below, sometimes the top of the Reaper window fails to render. What you see at the top, instead of the menus, transport, etc., is my desktop's background. When I click on this area, Reaper is deselected and the window behind (if there's any) is selected. This is temporarily fixed by pressing F11 twice to go in and out of full screen mode. The same happens when I open the midi editor as an undocked window. Docking and undocking it fixes the problem.
This behavior started with the 5979 release, so I downgraded to 5978, but a couple of days ago the problem appeared on 5978.
Someone at the Reaper forum suggested that this is a graphic card problem, but my drivers are updated and this only happens to Reaper. Another guy said that he had the same problem and it got fixed by modifying the Reaper.ini file, but couldn't remember the details. I took a look at the .ini file but got lost.
OS: Win 10 version 1809 KB4493509. AMD Ryzen 5 2600 processor. Dual monitors.
Thanks!