I suspect there might be an issue with Leadbolt. Leadbolt as installed on your app might be incompatible with version 145. You might try saving a copy of your app, then
on the copy either disable or remove Leadbolt . Tell us what happens?
Is the screen you show Screen1 or another screen?
Here is a list of current issues with version 1.45. Did you report the issue as indicated here:
Please use the App Inventor support forum category to report additional issues with this release. Mention you are using Leadbolt.
Regards,
Steve