Tooltip inside RadGridView inside RadTabItem

[Sean]

I have a gridview inside a tabitem. This contains NON-autogenerated columns. One of my columns has a textblock with a tooltip. There are two different issues. First is sometimes on initial load the tooltip does not work at all. Other times... the tooltip works but if I switch tabs and switch back to the original tab the tooltip no longer works.

Here is my basic code structure

<RadTabItem>
   <RadGridView>
      <Columns>
         <DataColumn>
            <CellTemplate>
               <TextBlock>
                  <ToolTip>