Why is there a "greyish" sheen to the active tab I'm using? Is there a way to turn this off?
Ok so I'm all for advancing technology and all that. But it seems with the latest update there's a "greyed out" look to the active tab I'm on, it makes the entire theme I have equipped look horrible. and It seems that every theme I enable this greyed-out look is there. Please tell me there's a way to turn this off? or if not......will you wonderful guys and gals at Mozilla be creating a way to turn this off?
Here's Hoping...
EGO II
Wšykne wótegrona (3)
This may not address your specific question, but may answer part of it...
Firefox 44 has a semi-opaque white-ish appearance to the main toolbar and corresponding tab when you use a custom theme. Depending on your OS, the size and coloration may vary.
If you use the Classic Theme Restorer extension, one of its toolbar options will clear the translucent background from the toolbar, but I don't know about the tab itself.
If you do not use CTR and don't want to change any other settings, you could consider using a custom style rule. For example: https://support.mozilla.org/questions/1106538#answer-836566. That one definitely is only for the toolbar and not the tab, as shown in the attached screen shot. (I didn't look into the tab background color at that time.)
A note that Firefox 45.0 on Linux will change in GTK needs. You will need GTK 3.4+ at minimum and GTK 3 Themes as otherwise Fx 45 will be unthemed white if a GTK 2 them is in use.