Sometimes, while working on Catia, the View pops-up by itself from "Parallel" to "Perspective".
Then I need to manually choose my favorite one, the "Parallel" one.
Why does this happens and how could I avoid this unwanted alteration?
Perhaps you are clicking "Fly Mode" instead of "Fit All In".
It will give you a pop-up message asking to switch to perspective projection. It will ask you Yes or No...the natural tendency is to click "Yes" when given those two choices on any pop up message.