Mozilla build 2001020513, also happened with 2001020208. When I use my 2-button USB mouse to right-click on the back button, a small box is displayed that behaves like a totally empty context menu. Right click is defined in my mouse driver as control-click as per Mac OS standard. When I hold down the control key and click with the left button, the same behavior occurs. This is immediately after starting up the browser, no weird sites or anything cause the behavior. Along with the decision to not allow holding mouseDown on the button, this reduces my choices to just clicking on the tiny arrow. Tried to find a dupe bug of this but I only found stuff about holding the mouse down, not right clicking. If you want to see what it looks like I'll take a screenshot. Mac OS 9.1.
seems something regressed. Bug 45961 was about this. OS: All - CC blake.
Second thoughts.. This could be another variant of bug 67435 "popups coming up empty all over the place"
Yeah, it's 67435. *** This bug has been marked as a duplicate of 67435 ***
verified dup. (And both back and fwd button are missing menus)