the problem is intermittent, and so far i could only reproduce it in hebrew wikipedia ( http://he.wikipedia.org ), but i doubt it has anything to do with RTL.
- select "enhanced editing toolbar" in preferences,
- enter "edit" state for a SHORT article long enough to have scrollbar in the editor, but not too long. try for something where the whole thing is no more than 3-4 "pgdn" from top to bottom (??)
- open the "Advance" menu
- grab the edge of browser, and narrow it to the point the toolbar takes two lines, i.e., some of the buttons drop to a second line.
now we can reporduce. as mentioned, the problem is intermittent, so reproduction depends on some luck. you may want to try different machines (faster vs. slower etc.), different connection speed (timing seems to be an issue - there is some race condition going on) or other variables.
the problem have been observed so far on FF and chrome, on win-7 and kubuntu-10.04
- at this point, "refresh", "super refresh" (i.e. shift-whatever on your browser) etc.
(remember - the "advance" menu is open and occupies 2 lines of buttons)
hit "refresh", shift-refresh, <ctrl> refresh etc.
if you are lucky, sooner or later the top of the textarea hides behind the toolbar.
if you reproduced, note that collapsing and reopening "advance" cures the problem - the textarea will have the correct size after closing and opening "advance".
tried to get similar results with other menus ("help", "special characters") - could not repro.
tried to get the same effect in en.wikipedia.org - failed. nl.wikipedia.org - failed.