Select and move (excluding white space?)

[claudekennilol]

So if the background (by background I don't mean the background layer, this is all one layer) is completely white, and I've got part of the image selected, is there a way to move just the selected portion while having pdn fill in the background instead of leaving it transparent/empty? 

[Daniels]

Add a new layer and move it below your picture. Then just fill it with white.

[Ego Eram Reputo]

So if the background ... is completely white, and I've got part of the image selected, is there a way to move just the selected portion while having pdn fill in the background instead of leaving it transparent/empty?

 

No.  Paint.NET treats white pixels just as any other pixels.  

 

Daniels has given you a clue to the solution - you need to use Layers.  

 

Use the lowest layer as the background and fill it with white.  Other image elements go on their own (otherwise transparent) layer(s).  Using this technique you can move the elements around, delete or resize them and you don't have to worry about making transparent 'holes' in the image.  This is the power of using Layers.