Firefox doesn't have context menu icons. Any icons you have in the context menu are added by add-ons. This should hide them:

@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);
/* The above line should appear only once in userChrome.css */

#contentAreaContextMenu image,
.textbox-contextmenu image,
#placesContext image {
  visibility: hidden !important;
}

Ok, thank, but it is odd I cannot immagine which extension is doing this... Your line is working, but not with the url bar (I right click on it and I see icons for "Undo", "Paste" and "Select all" item) nor with the bookmarks.

Please provide a list of extensions and maybe one of use will recognize the culprit. Or, maybe you're using Stylish and have a userstyle that you forgot about installing?

Try this;

Move your mouse to the top of the Firefox window, then right click. You will see a menu of the available toolbars. Select Customize. In the new window, look for the icon. When you find if, hold down the left button on it, and move it to where you want it to be. You can move any of the icons you want from here, but some icons are locked in place.

@FredMcD What I see are icons in the right click menu (and only when I click on the Firefox interface, apparently) @the-edmeister No Stylish, but: Adblock plus, context search, dom inspector, dark background switcher, epubreader, flashgot, https-everywhere, mega, noscript, printedit, youtubeall html5

Replace the original style I posted with the updated version. Does it get rid of the remaining unwanted icons?

• https://support.mozilla.org/questions/987599#answer-537670

YES! It does, thank you! How did you get the correct elements names? Using DOM inspector?

Picgi wrote:

YES! It does, thank you!

You're welcome.

Picgi wrote:

How did you get the correct elements names? Using DOM inspector? 

Yes. Using the "Find a node to inspect by clicking on it" button is tricky when it comes to menus. You have to bring up the context menu using the Menu key on the keyboard instead of right-clicking, otherwise what you right-clicked will be inspected.

• https://developer.mozilla.org/en-US/docs/DOM_Inspector

It is tricky indeed, but when I found a last thing to correct (icons that appear on tabs right-click menu) I found also the Element Inspector addon which let me select the element shift-right clicking. So I added a rule to the list:

..previous rules..

.menu-iconic-left {

 visibility: hidden !important;

}