Font form shows only a valid subset of fonts for a target application

In my long experience with several mobile IDE (xcode, QtCreator) a big lack is the choise of font on a device: always all system font are shown (example for QLabel), but often (always) the chosen font isn't valid on a device when i run it; how many time time to find a nice font for me and then verify if it exists on a device (with a run on it for each)!
My suggestion is to show only a valid subset of fonts for the current target (desktop or mobile device and so on...)