Hello, how do i remove the transparent overlay on the current tab / address bar / bookmark tab so that my persona theme: black shows without the overlay

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. 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]. See the following screen shot for what that does (on Windows 7, at least). [https://support.cdn.mozilla.net/media/uploads/images/2016-01-31-13-24-52-c1de72.png <img src="https://support.cdn.mozilla.net/media/uploads/images/2016-01-31-13-24-52-c1de72.png" width="500">]