Line thickness

[Stephen L]

All of a sudden the line thickness  for the shapes such as line and arrow are really thin and not very dark at all. I can't remember but I did increase the thickness before through one of the options.

From the forums they said to right click the objects such as the line which then creates a box around it and go to properties and increase the thickness there. I have done that but when I increase the thickness all it does is increase the image overall and does not make it thicker just bigger. 

Please advise as to why this has happened all of a sudden as the lines for the arrow and straight line used to be quite thock and dark whereas now they're very thin and not dark.

I am running version Nitro pro 12

Thank you for the assistance