ContextMenuStrip vanishes

Hi All,

I have a custom control to display a graph , to add graph data i added a contextmenustrip, with submenuitems like("Add-->AddItem-->AddMin

                                                                                                                                                                                              -->AddMax 

","Remove","Update"),when i move mouse over graph i am displaying tooltip with the coordinates.

Problem:

1.After right cliking i am displaying a contextmenustrip, some times it is vanishing.

i am suspecting tooltip is causing the problem.

can anyone tell me why this is happening.

Thanks and Regards

Yogeesh