In the past on slides where students need to sketch something, I have disabled buttons until after students have used the sketch tools using this code:
disabled: sketchStrokeCount(Sketch.sketch)=0 and
sketchPointCount(Sketch.sketch)=0
However, this does not work for checking to see if a student just used the new text tool. Does anyone have an idea of how I could also check to see if a student had written something with the text tool?