Hello, (note: newbie alert) I have only recently discovered MASON, and am already "hooked" -- it's a fantastic framework. During my first steps I have now encountered a (minor) snag, perhaps someone would be kind enough to supply the needed push forward. My first "own" simulation is a simple field with agents just running around. The basis is the very nice and instructive "School Yard" (Students) tutorial in the MASON manual; this example works fine for me in all its stages. I have then practically copy-pasted the code from the first stages of the tutorial into my own simulation, except that: -- all "buddy network" related stuff has been omitted; -- I am using a toroidal SparseGrid2D field (and SparseGridPortrayal2D), instead of Continuous2D* The following all works fine indeed: -- agents run around as expected, toroidal works, too; -- agents can be double-clicked to bring up their inspector in the Control Window; -- agents can be directly moved (dragged by mouse) The snag is about the green circle and black label used in the tutorial for marking the selected agent: In my code this does not work properly: -- when they are displayed permanently, i.e. parameter onlyCircleWhenSelected == false, both circle and label are showing up fine, so there is no problem with the graphics as such; -- But when onlyCircleWhenSelected == true, i.e. label and circle only to be displayed when the agent is selected, they are *not* shown. In other words, while a *double* click on the agent is processed properly (--> agent turns up in Inspector list), a *single* click for selecting the agent is not, and seems to be ignored. In case it matters: I am using MASON from within Eclipse, under Windows XP. (But as said, no problems with the tutorial, so that's probably not an issue.) What am I overlooking? Does agent selection via mouse-click perhaps work differently with a SparseGrid2D field (as compared to Continuous2D), or require special measures? At the moment I am not quite sure even in which direction to dig. Thanks in advance for any pointers! Cheers, Martin