How can l get the explorerbar groups to act like they do in outlook?

I have a explorerbar inside a websplitter that is 99.5% on the screen. My explorer has 10 groups and l want the groups to be at the botton not the top.

I have 

WebExplorerBar1.GroupContentsHeight = ((int)WebExplorerBar1.Height.Value - (GroupCount * 30));

but the WebExplorerBar1.Height.Value is 0 when loading.