In an attempt to figure out why my app wasn't launching (https://powerusers.microsoft.com/t5/General-Discussion/No-Data-Source-Provided-No-Item-to-Display-on...), I made a copy of the app so that I could go in and delete screens in order to see where the offending error was.
After deleting a few screens, I saved and closed. Upon running the test copy w/ deleted screens, the app launched perfectly, but with all screens (including the deleted ones)! I'm grateful and excited to see my app work, but surely something has to be wrong. The screens are still gone when I open it up to edit, so I don't know how I could make changes in the future to any of the slides I'd deleted.
What is going on here?
Your browser may have cached a copy of the App (with all the screens), try doing a forced refresh (Ctrl+F5) when it loads.
I tried that (also tried signing in and out a few times), but it's still showing all screens.
I tried making another test copy of the original app, but making no changes. The second test copy ALSO opens and runs without any issues, while the original app still doesn't work.
Ouch, ok, well was worth a shot, atleast you got it working with all of the screens editable, might be worth raising as an issue via the O365 admin portal
Actually any changes I make to the two test copies (and even the original app) aren't reflected when I rerun either of the test apps. After fiddling around with it, I'm able to make changes by editing the original app (which won't run), and then making a new copy of the edited original. I guess that works, but creating a new app everytime I need to make a change just doesn't seem like a good practice.
I've had similar issues when running Published Apps from the PowerApps portal, but force-refreshing(Ctrl+F5) the environment page before opening the app then makes the new changes show for me, can't understand why as the links to the apps remain the same, but that seemed to work for me.
Sorry that this didn't work for you, sounds like it might be a more serious issue