Hi,
this is great addon to stack. I tried it a little bit and it seems to work quite well. I made a question where you have to make a circle with geogebra to match with equation. You can move that circle and change radius. It just took me awhile to figure out how I can read coordinates and radius from gg-applet.
I used ggbApplet.registerObjectUpdateListener("A", "getCoords"); And
ggbApplet.registerObjectUpdateListener("r", "getValue");
And with getValue I could read the value of that slide thingy. Question is in Attachment. Sorry, it's in Finnish.