I know this is an old thread, but it's not actually even close to what he is asking. ctrl+alt+e pastes everything but the background. It creates an image defined by the foreground colour. I installed paint.net just to test this, thinking I'd found a solution, but it pastes the entire object with the background.
Windows 10 the latest iteration has deemed ctrl-alt-e to be a unique to itself key combination now, and I cannot use it in pspro9 any more, I have to continually him the toolbar and navigate, when it was as east as ctrl-c/ctrl-alt-e before.
It is frustrating enough that this feature is missed in other applications, but to have to now learn an entire new application over such things is ridiculous. I've used pspro9 for many many years, I know every aspect of it, I use it by default for everything, learning a new thing just to do a simple task, is frustrating.
So please, don't be so sure when you think you have an answer to something you don't really get the point of. afaics there is no paste as transparent selection in paint.net, and plugins or hunting down tutorials on how to achieve it, isn't an option.
