Ey, it should be I who should apologize, not you! 
Seriously, thanks for your assistance. I have seen that “text-minfilter linear” is exactly what i wanted. Furthermore, you were right, that grey zone was due to the board model (which is somewhat disturbing, as i haven’t seen it in the modeler; but, whatever the case, it’s a model’s problem, so i will re-check the modeler and/or the exporter at some point).
Now i will do some tests with other control types. All the issues minimally related to mouse events have been solved, so i guess this thread should fade out now… 