clickable and trackable.
I'm afraid I don't have a complete app where everything you need already exists and all you need to do is change the graphics.
To determine which item is clicked, one way to do it is to have an array of objects, each of which knows its position.
A click on the canvas triggers a search of the objects, checking to see if the click occurs inside of the rectangle it occupies.
You store the objects in a list where the first is at the back, and the last is the one on the top.
(The drawing order)
You search through the list and find the last item in the list that would have got the click.
Thats the selected one.
Not sure what you mean about trackable.
If you want to drag things about have a look at alex restrepo's classes: he has an example for little note windows all done in a canvas.