If you click on the toolbar button which has a lens with a minus sign inside the lens; you would be put into the zoom up mode.

Mark a rectangle on the screen; and TAD will figure out a way to put the current view into that marked out rectangle; effectively zooming up from the current view.

Zooming up is almost always available. Here is a simple trick:
For Zooming up, press Shift when dragging mouse to create a rectangle. The site will shrink down into that rectangle!

Watch out!!
Under no circumstances will the architect be allowed to shift out of your view. So just in case if the new view that you now be shifting to does not have the architect located there then you will find that the architect is forcefully taken out from its previous location and located to the centre of the new view

This would obviously mean that the earlier location of the architect – which you may have located very carefully – would get lost!