I'm trying to position the Edit Form dialog using the "center"  value   for the position property

I want the  Edit and Delete forms to display vertically centered in the visible part of viewport (which is the grid itself)  - the height (# of items) is variable so I'd like the forms to present such that no scrolling is required.

Will position:'center' do that or would I have to do something like specify absolute number of pixels from navigation bar which display at the bottom of the grid?

thanks!