It only happens inside OpenOffice. Typing some characters on a Persian keyboard
with Persian fonts messes up the previous characters. Here is how to re-produce it:

1- Install a Persian font, like B Lotus (from http://u.nu/6e273) or B Compset
(from http://u.nu/2e273) (The defect happens with all Persian fonts, not just
these two)
2- Open a document in OO Write
3- Select the newly installed font, lets say B Compset
4- Change the direction of the paragraph from LTR to RTL
5- Change your keyboard from English to Persian (Farsi)
6- Hold down the Shift key and type the following string of characters one after
another without any space between them: ? > < M N B V C X Z
7- Everything will mess up! (you also can have the same bug showing up by this
string of the characters (hold down the Shift key): | } { P O I U Y T

Other word processors, like AbiWord or MS Office do not have the same bug and
handle the same characters with no problem at all (the same font, the same
language, the same string of characters, no issue).