Custom Tasks List Not Working With Timeline And ProjectSummary WebParts

Hello,

I have created a custom list definition based on the Task content type. When I try to add the Timeline or the ProjectSummary web parts I cannot select the list. If I create a new Tasks list from the UI it is working.

I have also tried to provision the webparts and fix some of the properties utilizing the Object Model and the only progress I have made is showing the upcoming tasks in the ProjectSummary.

Any ideas.