@GreenGoo, first click on the cable to select it (it gets a little thicker). Then drag the object to where you want it. Keeping focus on the objects is a little tricky, but you should get by.

The intersection of the wire to the bulb should be restricted to the base of the bulb (connect a wire to the glass of the bulb should not make the light work).

I was making something similar when I found this. It seems we both have the same issue. f you line the wires to power the bulb, but then remove the wire touching the battery or the one touching that the bulb stays on (infinite loop between the other 2 wires I believe). You thought of any fix for this?

Yes that was my biggest problem. I tried to give ID's to the cables, but It it hasn't worked. I had some other methods. For example I tried to save them, in an array. I worked quite long on this, but with sh** solutions. :( You can download the sourcecode if you want. Maybe you can fix that. Later on in other scenarios I only used one big cable to ignore this. Therefore I wrote a method, that places it from one point to another. Watch here: http://www.greenfoot.org/scenarios/9271 If you fix that problem and if you upload your scenario, please tell me.