Perpendicular snapping and Cplane change in behaviour

Good Evening,

Sorry if this might have been answered previously, but a quick search on the forum didn’t bring anything new I haven’t tried already.
This afternoon I started modeling as normal, and I noticed that the behaviour of the O-snap, in particular the perpendicular one, changed since yesterday.
I used to be able to, when modeling in perspective view, click on a point, either on a line or on a surface, and then automatically being able to go ‘up’ in a straight line (if the line I was snapping from resided on the horizontal plane, I could start a line from that point and go up in a 90° angle from that plane, so changing direction, in the perspective view, from the XY plane into the Z axis). I am not able to do this anymore; any movement seems to be following the c-plane, usually set horizontal as per default. I am aware that there are particular line tools that allow me to do this, but I am sure I was able to do so with the normal line (and the move as well) tools.
I have checked all the options and nothing is out of place; there’s no tick on neither planar, ortho nor project, still any snap seems to behave like when ‘project’ is on (but it isn’t).
I have tried this on a different pc, and reinstalled Rhino to no avail.
Unless I have gone mad since yesterday and my memory has gone kaput, is there something that I am doing wrong from before, maybe something I activated by mistake?

Attached an image to show what I mean.
Thank you (and sorry if this has been asked before!).

If you’re talking about activating “Elevator Mode”, you need to press Ctrl when you click to go “up”.

Thank you very much for your reply (and sorry for the late response!).
For some strange reason, the tickbox for ‘project’, altough looking like it was off, it was indeed on! I believe that I might have caused some sort of glitch by tampering with the colours and interface settings a bit too much; those settings must have been picked up again when reinstalling Rhino giving the impression that nothing changed.
Now all working properly as usual (when pressing CTRL of course!).
Again, thank you very much for your help.