User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:15.0) Gecko/20100101 Firefox/15.0 Build ID: 20120825192204 Steps to reproduce: I am unable to add the Bookmark-Combobutton (the one that makes the Bookmark-Menu appear) to my toolbar. Actual results: Other buttons added at the same places show up, while the Bookmark-Combobutton fails to appear. It looks like it has never been added. It shows up, when I use the "customize"-function for the toolbars, but when not in this mode it does not appear. Expected results: The Button should be visible at the place it has been dragged (or otherwise added) to.

Did you test in safe mode and with a new profile? See https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

Yes, I did, the issue persists.

Depending on your toolbar configuration, this is a duplicate of bug 581238 and/or bug 631330.

(In reply to Aleksej [:Aleksej] from comment #3) > Depending on your toolbar configuration, this is a duplicate of bug 581238 > and/or bug 631330. Those two bugs are probably actually duplicates of each other.