Bug occured during work

I was working on my project and suddenly all became like this:

What can I do?
Thanks in advance

Hi Vladimir

Looks like a hardware (graphics display) issue. I see the emulator is on top of the Browser - best to minimise the Browser Window when running other programs, including the Emulator.

Close all other programs. If you can log out of App Inventor, do so. Close the Browser window and reboot your PC.


  1. Use FireFox. Chrome is also compatible with App Inventor but uses more memory.
  2. Ensure App Inventor is the King of the Browser - do not have many tabs for other websites
  3. Check your Broadband is good and ensure nobody else is taking up band width watching movies, playing games etc.
  4. Use the Companion with an Android device (phone) instead of the Emulator.
  5. Ensure your PC is not overheating.

Reload the browser:


thanks for your answer, i've tried few times to reload it, and it haven't change anything, but thanks anyway!

best regards,

Thanks a lot for the answer

  1. I've tried with firefox and it works fine!

best regards,

1 Like

Does your monitor double as a handball court?

I have never before seen such a huge resolution.

Maybe check your tray for graphics card settings and bring them down a bit?

I'm working on a dual monitor, the second one is a 2K monitor, i'll try to bring them down!

Try this server:

Do you get the same result?

1 Like

You may have disabled website CSS, such as via an accessibility setting in your browser. The positioning of the elements looks roughly correct, but all of the font, sizing, and color information (which are defined in the CSS) don't appear to be applied.