When I use Firefox every day, I often encounter the situation where the vertical tab cannot be automatically expanded when the mouse is moved over it. Please check the comparison of the pictures I uploaded. I am unhappy about this because it will affect our experience of using Firefox. I hope that this problem can be fixed by reporting it to you. The automatic expansion of vertical tabs returns to normal when I create a new Firefox window. My computer information is window 11 professional version 22H2 (x64), Intel chipset, Firefox version number is 144.0.2 (x64) I am a heavy user of Firefox. I agree with the values that Firefox adheres to, so I want to make it better. Thank you for taking the time to read my feedback. I am from China and would like to say hello to you.