Plus ( + ) sign appears after Volume, Send, etc. settings in some Sonar files

I noticed in several Sonar files that a  plus (+) sign has mysteriously appeared after numbers such as volume levels, send levels etc. I didn’t know what this was until I started to put in automation envelopes and realized that the envelopes always started on absolute zero in this mode  – even if the volume level was set above or below that – and that the volume fader did not shift with the envelope.
I actually like this mode of operation but I have no idea how to manually put Sonar (8.5) into this “plus’  mode, or what this mode is called. PDF help file came up empty, and “Sonar Power” couldn’t help me either. None of my templates start off in this mode, and I don’t know how it suddenly appeared in some files.
Anyone know what and how?

Thank you Scook for quick and precise answer.
 
I must have accidently hit the "O" key at some point in a couple of my files. Now I know its name I guess I will be able to find it in the help manuals.