Hi Grant Winney,
There is a know issue regarding tool tips in Q1 2011 SP1 (2011.1 11.419). We addressed the issue in our latest internal build (2011.1 11.510) which you can download from your account. I recommend that you try it. Also you should use a modified version of my previous code snippet:
If the issue still occurs, I would kindly ask you to open support ticket. There you can enclose a sample project where the issue is presented.
Best wishes,
Svett
the Telerik team
Q1’11 SP1 of RadControls for WinForms is available for
download; also available is the Q2'11
Roadmap for Telerik Windows Forms controls.