Diễn đàn hỗ trợ Firefox

I'm experiencing an unusual issue in Firefox: a CSS grid overlay is visible on various websites, while everything displays normally in other browsers (Chrome, Edge, etc.). This grid is not part of the actual website design and does not appear when using other browsers.

I haven’t activated any developer tools or extensions intentionally that would cause this behavior. Could you please help me identify what might be causing this and how to disable it?

Please create a new version of the browser app that supports the ability to use FileSystemAPI on directories, this is essential for working with a BeatBuddy project and SD cards that are saved on my computer using the online editor. Regards, Guy James