Bug 460699 added a <windowdragbox> element around the <tabs> element. Unfortunately a <windowdragbox> defaults to horizontal orient so the <tabs> element does not stretch to the width of the <tabbox> element as it should. Themes rely on the <tabs> element stretching to the width of the <tabbox> element to be able to draw their lines correctly. I don't know whether the <windowdragbox> works if other elements cover it.
It works as long as those elements are in the dragTags list here: http://mxr.mozilla.org/mozilla-central/source/toolkit/content/WindowDraggingUtils.jsm#51 or if they have mousethrough="always". Are there any arguments against giving windowdragbox vertical orient?
Created attachment 460060 [details] [diff] [review] Switch orient on pageInfo's windowdragbox In the mac version of pageInfo, we're ok as long as the element inside the windowdragbox keeps its centered position.
I'll land this sunday/monday