I tried to dimension an object. Now I have a blue dim line, no text, ticks, anything, that I cannot select to delete. What is the trick? And why does the text and ticks not show up?

To set the arrow and text size for dimensioning, I believe that you have to deselect everything, then do your set up, otherwise your update won't stick, and you'll be loosing even more hair with frustration. This initially also confused the hell out of me too, as I came from Solidworks, and if you decided to change one size of font in SW's, every other in that same group would also be updated- probably like AutoCAD?

While we're here, have you tried QCad by Ribbonsoft? You may prefer to use this over ViaCAD 2D. I use QCad in conjunction with ViaCAD (by importing from DXF). The combination works very well.