PDFpen on Mac is a promising replacement of PDF Annotator in Windows. But the developers really should get a tablet and make their software ready for it. At least it is more or less usable with this: You can stop PDFpen from switching back to the arrow tool after each stroke with the scribble tool by double clicking the scribble tool.

Of course you will find out those things just after asking the developer how to do exactly that. So let’s see what they will say.

But one really annoying last thing is to avoid those selection overlays of the newly created stroke. Maybe some other secret clicking trick will do that as well.