Issue with DayPilot, ASP.net AJAX Control toolkit

There should be no conflict with the Ajax Control Toolkit. The toolkit is used in some of the examples and it works fine.

There might be an issue with placing a DayPilot control inside a tab that is not visible on startup, please see here:

http://forums.daypilot.org/Topic.aspx/395/scrollpositionhour_not_working_with_daypilotcalendar_in_ajax

But still it shouldn't cause the whole page to disappear.

• Have you tried to remove the Obout controls to see if DayPilot conflicts with them?
• Do you see any JavaScript error?

Yes we have tried removing obout controls and the error is still there.

There is a JavaScript error - SCRIPT5007: Unable to get value of the property 'indexOf': object is null or undefined
If you expand the ScriptResource.axd it looks like the AjaxControlToolkit Tab control is the one that gives the problem.

We tried the open source version of DayPilot and it works without any issues.
We removed the tab and just placed the DayPilot control on the page and it works without any issues.

We have included both Calendar and month in 2 different divs and hide respective ones based on what user selects.
We are not hiding any tabs so the scenario in the link you have mentioned does not apply. We tried some of the things mentioned in the post.

Any hints would be helpful to troubleshoot this further. Why does the Lite version work without any issues?

Update:
1) We created a new page and put the DayPilot Control on it (Calendar and Month) - Tested in IE 9 - Works Fine
2) Added a tabcontrol and included the Daypilot control on one of the tabs - and could reproduce the error.

AjaxControlToolkit Version - 50508

Any updates or hints?

"The toolkit is used in some of the examples ..." I have looked through the entire DayPilot Pro demo and source, and there are no examples that use the Ajax Control Toolkit, and it is not included as a resource. Am I missing something?