Hi, I would like to ask, what is $chr(9) (Ctrl+I) meant for? For me, it aligns popups properly, but I saw in a screenshot that in a dialog, it returned a box that I did not see for myself. (http://www.mirc.net/download/screenshots/1065038802.png)

So, what is it originally meant for, is it meant for aligning popups properly so that:

AA --- blah
AAA --- blah

will appear as

AA --- blah
AAA -- blah

?

It's the TAB character.

Iori is right, it is a tab character. Dialog lists do now howver support showing a tab, so they are shown as a box instead. What you could do is replace it with a different character using $replace or perhaps remove it for the dialog.

However, I see it as nothing. Does it not show up only in Windows XP?

its all dependant on the font being used. The user might have custimized windows themes making dialog window fonts different in which case their font might show a [].