User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:59.0) Gecko/20100101 Firefox/59.0 Build ID: 20180215111455 Steps to reproduce: I have 2 monitors attached to my computer, one that runs at the standard 60hz and one that runs at 144hz. There are a few graphical bugs that happen with Firefox when running on a high refresh monitor. Sometimes, maximizing the window will cause the entire window of Firefox to turn black. Clicking and dragging the window from one monitor to the other will cause the image to display normally on the 60hz monitor, and still remain black on the 144hz monitor. In addition, the drop down suggestion menu that shows up when you begin typing a URL or search term will also be blacked out. This also will show correctly on the 60hz monitor. Actual results: In both cases, if the window is partially on both monitors, no graphical bugs will appear on the 60hz monitor while maintaining on the 144hz monitor. Graphical bugs do not show up on the 60hz monitor, even after multiple attempts to make them appear. Expected results: Windows and drop down menus should not be displaying all black.

Can you tell if this is a recent problem, or has it been around for a long time?

I switched back to Firefox when Quantum released. I have experienced it since the first version of Quantum, so it's been a bug for a couple of months.