So I am new to drawing and "Paint.Net" in general, so I expected to run into some problems; mainly this one. I created a new layer and was trying to draw a line but it wont show. All t shows is the resizing tool for the line but not the actual line itself. IT happened to me last night so I tested it before I did some work today and it worked. I'm doing transparent drawings if that effets it at all. I'll attached photos.