It's a function several pieces of software: the font / font renderer and the toolkit the edit widget came from, and sadly the particular application. That's why there are often inconsistencies across systems and softwares. In Windows, the consistency issue at least is better, because one vendor is responsible for more things.
On your linux box where you "only have us-eng installed", you might in fact get BiDi anyway in certain cases (say, for example, in a browser). And to get it *everywhere*, you might have to work very hard.
Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
Want more info? How to link or
or How to display code and escape characters
are good places to start.