when i customize my toolbar and close, the icons are not in the places i put them. how do i make my toolbar set up stay in place?

below file/edit/view/history/bookmarks/tools/help menu line, on second line I have added icons for print, reopen closed tab, session manager, (xmarks)synchronize now, my xmarks, home,duckduckgo, woolik search, stumbleupon, you tube, do not track me, mask me, better privacy, https addon, zoom out zoom in, back forward, private browsing toggle. on the third line i have added icons for gmail-open in a new tab, gmail checker, gmail notifier, last pass and the address bar. there are 2 to 4 separator lines between the icons, grouping like icons, i.e., security, search engines, gmail, etc. each time i close Firefox and then reopen, the icons are no longer in the order i placed them, with separators, or they are not visible and i have to r.click. select "customize," and re-drag and drop the icons and separators where i want them. i am a very, very beginner at this all, but drag and drop i know. why don't the icons/seperators stay in place?? thank you for you help...a. 09 fev. 2013 16h03.