I have the same version of Ds4.5 on two different computers one has it one does not so
How do I get Edit Figure Geometry in DS4.5 From Drop Down Menu?
Did you customize menus on one of them?
It could be but I have no recollection as to how I did.
I can't even remember how to move the tabs to the side of the windows instead of the top
To get the new menus you will need to reset them - if you haven't done too much customisation just reload the layout, if you have delete the menus.dsx file from C:\Users\yourname\AppData\Roaming\DAZ 3D\Studio 4 (which will remove all menu customisations, but leave actions and layouts in place).
The tab option is in Edit>Preferences>Interface, I think.