When multi selecting objects by picking and these objects are within groups so the ctrl-shift keys are pressed - then pan with the rmb pressed to continue selecting and the view rotates - I figured out the way to disable the rotating view is to let go of the ctrl button during the pan, good …. Couldn’t find this in the help file?
While looking for this solution in the help file, it seems the Ortho option doesn’t constrain the view rotation to horizontal or vertical.
Hi, Brian,
Wow. Talk about busy fingers! The reason it’s not in the Help file is that no one has ever mentioned the problem before.
Thanks for the mention of the Ortho constraint. It should really work like this:
Press Shift after starting the camera rotate with RMB, Control+RMB, or Ctrl+Alt to lock the camera rotation horizontally or vertically. The direction is determined by the relative location of the cursor to the point where the right mouse button was pushed down. If the cursor is more to the left or right than up or down, the rotation is locked horizontally, and vice versa.
Thanks Margaret, it takes a bit of getting used to the various navigation results between perspective/parallel views, pressing the extra keys before/ after starting the operation but I think I’ve got it now. Must be a male thing (well, some fo us) to crash on trying to get things working, instead of reading the instructions……
I don’t think it’s quite a male thing. I only read the instructions as a last resort myself. 
FTFY 