Thunderbird window automatic resizing

[PaoloAiello]

If you leave Thunderbird running without performing any UI operations, the window occasionally automatically resizes to a default size. I don't know if this happens when new messages arrive or if it's something else. It's certainly very annoying and completely unnecessary.

[siffemcon]

Try this.

Open your TB profile:

- TB menu > Help > Troubleshooting Information

-  click the Application Basics > Profile Folder 'Open Folder' button

- close TB and delete the xulstore.json file in the profile folder

- restart TB

[PaoloAiello]

Thanks, but it doesn't work. The window keeps resizing (the height is reduced, while the width remains the same).

[siffemcon]

Does that also happen in https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird/?