[SOLVED]Problem with userChrome_customization.css + FF87.0b2 64bit

[Vikijaka]

Hello there,

my userChrome_customization isn't working properly anymore.

.tabbrowser-tab:not([pinned]) {
		max-width: 120px !important;
		min-width: 20px !important;
	}

This is the only Way i found to shrink/minimize the default Tab Width so far.

^This is what is happening currently, when i close a Tab, the "new tab plus" isn't jumping back to the last opened Tab anymore.
It seems so, that the tab isn't getting closed, instead i'll get this blank space. After restarting FF, the blank space is gone but the "closed" tab is back.
When i remove my customization, the "new tab plus" is working as intended.

To fix this I tried to reinstall Firefox(latest stable+new profile) and shadowfox.

Win 10 64bit
FireFox 87.0 b2 + no extension

Thank you

also, since Firefox 57, but i don't now how to categorize it to make a proper case for this.->
with shadowfox ->

without shadowfox ->

[Vikijaka]

Fixed via

.tabbrowser-tab[fadein]:not([pinned]) {
    max-width: 120px !important;
    min-width: 20px !important;
}

i learned that there is some kind of "ghost" tab, which is bugging out nowadays. but with the fadein syntax it isn't anymore