With this code your applet it's an equivalent of Cinnamon Panel Launcher

[ghost]

See, you need to decide if you want to remove a launcher or not (currently not removed) when is dragged to cinnamon panel launcher, this also could be used to remove a launcher by other external application.

If you want to do this, you need implement the function:

removeLauncher: function (appGroup) {
    //Add code here to remove the launcher if you want.
},

[jake-phy]

Very good, thank you.