Changing the scale in the Edit pallet only changes the scale of the selected object – not the scale of the drawing generally. You can have objects on a single layer of a drawing at different scales, but generally it's not a good idea (it gets very confusing).
When you open a new drawing, go to Windows >> Layers/Pages... and alter the scale of the initial layer (Layer0) to the scale you want. Then everything you draw (on that layer) will be at this scale, unless you change it in the edit pallet.
Having objects at different scales on different layers of a drawing is just fine. So, say 1:12 for the main drawing (on one layer) and 1:2 or 1:1 for detail (on another layer).
RealCADD will open a new drawing at the scale of the last drawing you did – in your case 1/12. So you need to change it before you draw anything. So after doing a 1/1 drawing it's likely that the next drawing you create will be at 1/1 until you change it under Windows >> Layers/Pages...
Cheers -- George