QuickInfo not working

I am not able to get QuickInfo to work.

We have our own language XML, and I put IntelliPromptQuickInfoSupported="True" as an attribute at the top:

<SyntaxLanguage Key="MIN" LanguageDefinitionVersion="4.0" Secure="True" IntelliPromptQuickInfoSupported="True" WordContainsAdditionalCharacters="@_" ...

I have also implemented a Mouse Hover event handler, and the basic tool tip text works, but not the QuickInfo tool tip. I step through it and know the ViewMouseHoever is being called. Please help.

void se_ViewMouseHover(object sender, EditorViewMouseEventArgs e)
{
//e.ToolTipText = "This simple tool tip text works";
IntelliPromptQuickInfo qi = m_se.IntelliPrompt.QuickInfo;
qi.Show(e.Location, "Rich tooltip" ); // Does nothing
}