Samuel Peisakhovich Geisberg was left handed... wanna kinow how I know?
Because if you are right handed, when you are in a numerical value box anywhere in CREO, if you are at the end of the text, when you click and drag to the left to select text, your arm moves naturally through an arc down and to the left. But, the only way CREO can select text in a box is if you click and drag up and to the left (or down and to the right.)
All those windows style entry boxes didn't exist when he was programming.
I've often wondered why the text selection process was screwy, maybe this is why. I've gotten to where I just double click the box to highlight everything so I do have to deal with text selection oddities.
Cool video of Pro/Engineer first release (in french).