Hello,
I am upgrading from 5.3. I have been messing around with a blank project since I posted this question. I am able to now work within the editor normally. The only change I made was to turn off Lumen, close the project, re-open project, then assign Lumen again. Strange. I then tried to upgrade my existing 5.3 project and it is impossible to navigate. It is basically frozen. At this point I will re-create my project in 5.4. Perhaps this will help me understand what the problem is.