Try right clicking on the pipe and selecting "Pipe Slope Editing" from the menu options. You may have to find a Plant specific fly out.
Are you running into the issue where you change the pipe slope after placing a pipe run and the components at the end of the slope disconnect?
If that's the case it seems to be a known issue in the software. It doesn't have the ability to automatically move all the components that are attached at the end of the pipe run.
The only workaround is to change the slope, then go back and manually move the pipe/components and re-connect manually.
Yes that is my problem if I change the slope of the line everything else changes, I also can not use the grab points and move the components up the slope of the pipe.
Was this ever resolved for 2012? I still seem to be unable to modify pipe slopes after adding components.
I tried to use PLANTSLOPETHREHOLDANGLE which was orignally set to 5, and when i change it to the max at 45 it still does not work.