MessageBox does not show all characters

The font is my system font... Wat do?

EDIT: Adding 6 spaces at the end of the string solves the problem, WTF.

Using my psychic guessing power, I'd say there's a bug in the font metrics system. It's not measuring the strings correctly, so think it's allocated enough horizontal space in the message box for your string, even though it hasn't. This is why it works when you pad your string with spaces (it reserves space for them, which is then used to render your "real" string). I'd confirm this by changing the system font to something a little more standard (i.e. whatever they ship with).

I'm guessing you're using Mono, so this might be a bug there or it might be a bug in your Window Manager. Do other applications on your system have truncated alert views or dialog items? If so, it's a WM bug. If not, it might well be a Mono bug.