Customize context menu to eliminate this option "Open Link in a New private window"

Where I can read the API of CSS used by Firefox?
I manged to find these helpful lines of code:
//////////start code:
/*** REMOVE items from image context menu **/
Email Image… /
Set Image as Desktop Background… (and preceding separator) /
#context-sep-setbackground, #context-setDesktopBackground,
Inspect Accessibility Properties */
display: none !important;
///////////////end code
but if I want to dig deeper and get rid of other options, I cant without a reference book. So, where is this specific for firefox API CSS reference ?
Thank you.

Hi Teodor,

You may find more information about CSS usage in Firefox on this page.

Please note that the Reps section isn’t the right category for your technical question. You may want to post on Firefox Development next time. In the meantime, I moved your question there.

1 Like

Thank you !
I also want to declare a “error”… I already have installed, actually for a long time, this multi tab rows, I keep around 50 tabs in my browser. I have no idea how to write the CSS script myself, I just copy it from diverse locations and discussions about this subject, and wisel around, with a ton of browser restarts until I managed to make it work. BUT… by 1week or so, I have installed w11 , from my w7 I had before. And on this w11 im right now, this multi tab CSS script worked, but with errors. So on my w7 it worked flawlessly for a very long time I may add, but here in the new w11, mystery errors. The error was like this: when I was making a new tab from the [+] button, it was adding a mysterious empty space between tabs. And inside this empty space some tabs dissapeard ,no visibility, but rarely. What was consistent was this space all the time I was making a new tab.
THE Solution: luckily, after I installed WinUtil it uninstalled a lot of preinstalled microsoft programs and probably some windows settings as well. After I restarted windows for those settings to take effect, when I opened my FF browser, all the tabs were as I had them before in w7, with absolutly no ‘spacing’ problem between tabs on opening.
So my advice is to send this error further on the line, to people there that are working on FF, and make them aware of this particular error I encounter and its solution - again, particularly for w11.
Win11 is having like a NEW and Glorious shell over the old and trusty User interface and settings, legacy of wXP and w7. And this new shell is “f*king” everything and everybody. Is my observation.
In conclusion, right now, everything is fine and working as it should be. Also it will be cool to re-integrate this multi-row-tabs function directly into browser settings in the near future.
I hope it helps anybody.