LastOpened can bork projects after deleting a screen

[ewpatton]

Describe the bug

After deleting a screen, the lastopened project property does not get properly reset and can cause App Inventor to fail if the screen named no longer exists. I suggest we both reset the lastopened property to Screen1 when this happen as well as put a guard in that if the screen doesn't exist we open Screen1 as well.

Affects

• Designer
• Blocks editor
• Projects Explorer
• Android Companion
• iOS Companion
• Android Compiled APK/AAB
• iOS Compiled IPA
• Buildserver
• Debugging
• Other... (please describe)

Expected behavior

Projects should reopen after deleting a screen.

Steps to reproduce

Not 100% sure yet, but I expect deleting a screen and then immediately closing the window should trigger the failure mode.

[apexpdl]

Hey! I can take a look at this and try to reproduce it locally. If that’s okay, could you assign it to me while I work on a fix?

[ewpatton]

@apexpdl Go ahead.

[Vaishnavi3-hub]

Hi @ewpatton

I’ve gone through the issue description and started tracing the related code paths locally to understand where the state gets out of sync.

From an initial look, this seems related to how the component lifecycle/state is handled during the specific user action described.
My plan would be to:

• Reproduce the issue locally
• Identify the exact condition causing the incorrect behavior
• Implement a fix that aligns with existing patterns in the codebase
• Add/update tests if applicable

I’ve gone through the issue description for #<3689> and started tracing the related code paths locally to understand where the state gets out of sync.

Before proceeding further, I wanted to check if it’s okay for me to take this issue and submit a PR.

Thanks for your time and for maintaining this project.

[padhle-yrr-adi]

@ewpatton hyy, i m new to oen source....can you plz help me out? how can i join discussion group ?

[SusanRatiLane]

@ewpatton hyy, i m new to oen source....can you plz help me out? how can i join discussion group ?

Please join our community forum. https://community.appinventor.mit.edu/

Whether or not you are planning to apply to Google Summer of Code, our information will help you get started: https://community.appinventor.mit.edu/t/google-summer-of-code-gsoc-2026/163196

[Harshal135701]

I have submitted a PR that fixes this issue: #3690. It guards against errors when restoring the last opened screen if the screen has been deleted. Please take a look when you get a chance. Thanks!

[SusanRatiLane]

Above referenced PR was closed because it did not compile.