Perhaps I'm thinking of a different CAD software... Waaaaay back when.
Or possibly a 3 button mouse, whereby the middle button was pan...? It would be before the invention of the mouse wheel also.
My reason, because I use a universal trackball instead of a mouse - they brought out super cool features and a gajillion buttons for use on a single mouse, but they're all RIGHT handed, and I... am not.
Currently using a Kensington Magic Mouse trackball, which works well, as it has the scroll ring on it in place of a scroll wheel. Also trying the Logitech M570, a thumb operated trackball, about the size of a chunky mouse. The problem with this is that it's a bit tricky to hold down the scroll wheel and roll the trackball at the same time. Later today, should be picking up one of those pen style mice for comparison.
Short story, I have Parkinson's disease, and was originally right handed, but since PD attacks the small motion repeated functions, like typing, and mouse use, I've been lucky enough to switch to a left handed setup - some days are better than others.
I also have one of those small hand-held universal trackballs with a laser pointer, the problem with that is that to type, I have to put it down, whereas a regular mouse/trackball, I just life my hand off and the mouse/trackball stays put.
So I was thinking it would be easier to separate the operations to improve the ease of the function.
Make any sense?
Mark