Does this happen when you click Filters on the toolbar? Did it ever work before?
Some macOS users report their Filters window is blank when they make it float instead of docked into the main window:
If this sounds like your problem use View > Layout > Restore Default Layout and try again. Or, you can delete your settings file ~/Library/Preferences/com.meltytech.Shotcut.plist.
This is an OpenGL failure, but it works for me on all of my Macs. If you enabled the hidden, unsupported GPU processing feature turn it off. If you did not, then this is a compatibility issue between the GUI library we use and your system that I will not attempt to fix. Some parts of the Shotcut UI use OpenGL to draw, and OpenGL is notorious for interoperability issues. Either it works for you or it does not. Perhaps in a couple of years when we upgrade to a major new version of the GUI library that uses Metal instead of OpenGL, it will work better.