Picture editor problems...

I'm working a lot with alpha channels, and I'm having problem figuring a few things out.

* I'm trying to copy from one picture to another (both use the alpha channel). When I paste a selection, I want to paste both the RGB channels and the alpha channel content of the selection. It only paste the RGB stuff, so it looks like I must copy the stuff in the alpha channel separately (which is a bit time consuming, and if I don't remember wrong, it doesn't work with fully transparent pixels).

* I want to quickly hide the alpha channel, so nothing in the image becomes semi-transparent (that makes a lot of things a whole easier to see and edit), and then be able to show the alpha channel again. The only way I can think of right now is to discard the alpha channel completely.

* I'd like a way to use the fill tool on alpha channels, but getting the information about how the area looks from the RGB channels. This way I could for example easily fill a yellow area with transparency.