Hello Doug Beard,
It seems that you set the RadToolTipManager property to False with the use of AJAX.
However, please note that AJAX is all about partial page updates. Likely, the container which holds the RadToolTipManager does not get updated as a result of this AJAX request. As a result, all changes to the state of its child controls are not transferred from the server to the client.
You can easily test for this by adding a <asp:TextBox> underneath the RadToolTipManager, and then setting its Visible property on the server. If my assumptions are correct you will notice that no change occurs on the client-side and the textbox would still be visible.
the Telerik team
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