While using windows XP, I was facing a problem. I was working on a multilingual web site. we were showing tool tips to help user to understand what a particular button will do or where a link points. The tool tips were working fine for language which uses English language characters. But in case of other characters (read unicode) such as Chinese or Arabic, it showed small boxes instead of letters.
I had to do lot of research on the internet (googling is my first habit) and here is what I found:
To set your tooltip font to be able to display Unicode characters:
Right click on the desktop, pick Properties -> Appearance -> Advanced ->Item: ToolTip, then set the font to Arial Unicode MS or other large font.
This will show unicode characters in the tool tip.