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).

@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.

@FlyingRabidUnicornPig, you enter a window coordinate in the parameter and it returns the universal coordinate. The top-left corner of the window in window coordinates is always (0, 0), no matter what scrolling has taken place; however, in universal coordinates, (0, 0) is always the top-left corner of the scrolling area. So, for example, if you wanted to know how far the background can scroll to the left in order to get to the left edge of the universe (or the left-most scrolling limit), you can use 'int remainingScrollToLeft = getWorld().getUnivX(0);'