There are times that I like to have the modifier keys as a shortcut for changing between solution 1 and solution 2. There are times where it is a slight inconvenience and I find that I have to tap one of those keys a few more times to get the result I want, because I had tapped it while trying to pan my window so that I could get the view I wanted. Here I say it is a slight inconvenience because the solution is either obviously right or obviously wrong.
And then there are times when constructing a complex profile by VPI. When I press Ctrl it alternates between parabolic curve, circular curve, and asymmetric curve. I don't know what is done elsewhere, and I can understand that some engineers may switch between them depending on the client. Everything I work on uses parabolic curves.
Why, you ask, do I use Ctrl in the first place? Perhaps to modify my window conditions such as exaggeration. Perhaps because I'm copying and pasting numbers to enter the VPI station and elevation.
This is a singificant inconvenience, because it's not clearly obvious that it's about to construct a circular or asymmetric curve. Yes, I can make sure that the settings show me what vertical curve type is about to be placed, but do I want to look at that every time?
Where this becomes a major inconvenience is when I've constructed the profile using what I thought was parabolic curves, then notice they're circular, and now I'll have to reconstruct the entire thing because it's not as simple as selecting the curve and switching between circular and parabolic.
That said, I'd like to see an enhancement that allows the user to switch between circular and parabolic curvature after it had been constructed just as we can swap between sag and crest.
And I'd like to see an enhancement that avoids this uncertainty in the first place by allowing users to lock in one vertical curve type.