App Works but Coding Screen Freezes

I’m having a problem where the app will run its “preview” smoothly, and I can edit the code on all of the pages except one. When I open the page with the most code/variables, it freezes. I can’t move around the screen to see all the code, edit the code, or even re-load the page. I have to quit and re-login. Any suggestions/reasons why this is?