I have Firefox set to reopen the previous session whenever the browser is launched. I normally have multiple windows open; I have different tabs in different windows so as to organize them and make it easier to access a particular tab / type of content. I can mouseover on the toolbar and select a tab via preview. Until recently, whenever Firefox relaunched my previous session, it kept the arrangement of the windows intact (from right to left in the preview). After a recent update, I assume, Firefox is now no keeps them in the same arrangement; aside from my first window, all the others now randomly (or so it seems to me) rearrange themselves whenever the browser launches. I can reorder them by selectively closing and reopening windows, but it's getting tedious, and the arrangement only lasts for the current session. Once I shut down and restart my computer the windows are, once again, rearranged to no apparent rhyme or reason. This is getting really frustrating.