pressing Enter does nothing

Of course! It work ONLY when You create dimension (room, wall, etc.) NOT AFTER. That's mean You have to exercise.

so an example. i want to edit a dimension and set to an exact length

Is time to decide. Previously You want to change ALL and I've offer You a solution (even You don't like it).
It work also for individual items (Advanced Editing).

trying to get all my individual dimensions to the exact length i want

How You explain that: I & others CAN with existing solutions and You don't???

a right click on the...

Did You ever know what is behind of this action (code)? Or behind on a simple left click?
You have to consider that: nothing happen without a guy who program it; and is not easy (not for me).

i waste HOURS and HOURS trying to get all my individual dimensions to the exact length

It appear You have enough time to lose trying what others already discover a solution and already share it with you.

you suggest TWO extra Plugins AND a 'minitip'

When You or Your parents make shopping at supermarket why don't buy only one small product to eat? It's not enough to You only one potato?
So, while You by more because You need more, why don't accept to install needed plugins (IT'S FREE, WE MAKE IT FOR FREE and INTEND TO KEEP IT FREE)???
Or maybe You're right: some of us are dump to make such useless things.

i was going to include a screen shot, but appears that is not possible

Seriously???
Have You try to ???
Have You read the specific tread on Gallery???
Have You ask Your self how others can ?