Page layout in right-to-left languages
Fragment of a discussion from Support/LiquidThreads
Have you looked at it? The sidebar appears at the foot of the page.
This is not occuring for me when I set "?uselang=ar" or "?uselang=he" (with either the Monobook or newer Vector skin).
You should specify the URL of the page where this occurs (and which skin you currently use). Possibly it's a limitation of your current brower, or a bug in your custom .js / .css for a specific skin.