Maybe because GadTools is designed in such a retarded way ?
GadTools is not size or font-sensitive, a Gadget declared with a height of 12 pixel, will allways stay 12 pixels, even if you run a 20 pixel font ...
Noone, and I mean noone should have used GadTools in the last 10 years or so !!
There is MUI, there is Triton, BGUI, even StormWizard and ReAction for those who like to suffer, so there is no sane reason to use GadTools, unless you plan your SW to run on a stock A500+/A600 .....