Xfce Display Settings confirmation dialog occasionally blank
Occasionally when clicking "Apply" on a display settings change, the display confirmation box (with the countdown) pops up, but only the border is visible, the inside is empty. The window cannot be clicked in, nothing seems to work there. Clicking the X in the corner eventually leads Xfce to say that the application is not responding and asks to exit, though after the display confirmation timeout, the box goes away. Subsequent Apply actions may or may not trigger the same thing happening.
This has been observed on multiple platforms, both a desktop and a laptop, on both Xubuntu 20.04 and 21.04. Running the application in the command line yields no output when the issue occurs. It can be reliably triggered by repeatedly disabling a monitor and cancelling out, but most any change can result in this happening.
Attached is a screenshot showing the result of the bug.