Different part revisions in drawing

Hi,

I have created a drawing of a part and checked it into workgroup PDM vault.

I then checked it out later to make a revision, and I detailed this revison on a new sheet on the drawing, then checked the drawing back in the vault.

When you check this drawing out of the vault, both revisions are there in the drawing, which I like.

Sheet 1 shows the original revion (which I can right click and open), and sheet 2 shows the new revison (which i can right click and open)

I have now done the same exercise on another part, and now the drawing will only show the new revision. This means dimensions fall down on the orginal dimensioned drawing on sheet 1. I don't want this to happen, I like the fact you can go through the sheets seeing the original drawing, and then revision drawings.

I have noticed on the part which worked that when I open the original part off the drawing, the part number in the tree says > PART NUMBER (Default<_Display State 1>),

When I open the revison 2 off the drawing it shows PART NUMBER (New Output<_Display State 2>),

As I write this I can see it is to do with display states, but I have not used them, can someone explain how to use them to acheive different vevisions on different drawing sheets?

SolidworksWorkgroup Pdm