First off, I'm running 65.0.1 on Windows 10 on a new laptop I purchased in the last month. I'm having trouble figuring out how to describe the issue I'm having, and I'm not sure if I have all of the terminology correct. I've tried searching for others with similar issues and haven't found this particular problem. The problem I am having occurs occasionally after waking from sleep. On some (but not all) windows, certain menu elements will render on top of my screen and will be unresponsive. For example, this most commonly occurs with the address bar drop down suggestions, but also occurs with permission boxes such as requesting location access. I believe I have also seen it happen with the downloads box (what comes up when clicking the down arrow, not the separate window that comes up with Ctrl+J). When the problem occurs, these elements render on top of the screen and block anything behind them. They are also unresponsive to any input. They will persist in the same location on screen that they initially appeared, and will not move with the window if I move the window to another part of the screen. For example, the address bar takes up the full width of the screen when maximized. If the suggestions box gets stuck across the whole screen, then moving the window to fill half of the screen doesn't cause the stuck element to resize as well. These stuck elements are also specific to the particular Firefox window, and do not render over top of a separate window or other applications. It is also possible for them to stack, as I have had the suggestions box and a permissions box stuck simultaneously. I can get them to go away a few ways. One is to re-activate the element, which allows me to interact with it normally, at which point it will disappear when it should. For example, if the address bar suggestions are stuck on top, I can start typing in the address bar. This causes new suggestions to pop up, at which point I can interact with it normally again, and it will disappear as it normally would (such as after selecting a suggestion or cancelling out). Sometimes this is more difficult, though, as in the example with the location permission box. I would have to go to a website that triggers that box to appear, at which point I can interact with it and close it by selecting either option on it. At this point it is easier to clear the stuck box the second way, which is to close and reopen the entire window. When the specific window that the UI element is tied to closes, it will also disappear. I've noticed this occurs after putting my laptop to sleep and then waking it back up. It doesn't happen consistently, however, and I can't quite figure out what other conditions are necessary to replicate it.