Offset between annotation dimension and plane

[BWS]

Hello,

How do I create an offset between annotation dimension and a plane?

See picture:

If I change the height of this cube, the dimension doesn't keep the offset, but disappears behind the cube.

I want these dimensions to automatically move in the same direction as the cube.

[AmitDeshpande]

I don't think it's possible to have the dimension update automatically.  Once shown and then modified, the dimension will need to be moved manually.