Textarea incorrectly displayed

Hi,

Does someone know how could I prevent the G and the Y (and in fact every letter going under the writing line) to have its bottom cut in some zoom mode ?
I am using a single line dynamic text area. The problem is occuring with each font I have tried. It has the default height it had when created. Resizing the textarea only makes its content bigger and keeps the problem.

Thanks for your help,
Khaan