Display issue while running application on 400*800 resolution mobile..

I am running my application on htc Tmobile which has 480*800 resolution. While running my application i found that in tree control the characters are getting jumble up. In tree control i have to click 2 times on perticular item to open the next thing. Where as in other mobile like samsung its working fine without any problem.

Can any one suggest how to tackle this issue.

Thanks.