We have noticed, when you change the scaling of your display to something else then 100%, the drop downs in Event Viewer don't work anymore. Changing back to 100% instantly makes the drop downs working again.
This bug is present since 1803, and still isn't fixed 1809 BUILD 18262.1000.
The bug was reported already in the past...
Thanks to the new DPI Awareness column in taskmanager in the preview build, I can add following info to this case:
