The description for append, insertAfter and insertBefore I believe are not defined correctly in the TypeScript definition file.

For example, for append(item, referenceItem ) as defined here:
http://docs.telerik.com/kendo-ui/api/web/panelbar#methods-append

can be JSON or a string (text, url, etc.)

However, the TypeScript definition defines both as strings.

Do these interfaces need to be expanded to accept JSON object directly?

Also the referenceItem parameters says that it can be omitted, but the interface does not indicate that with a '?'.

Hi Matthias,

Thank you for noticing this, seems the PanelBar and Menu methods were incorrectly described, which causes their TypeScript definitions to be wrong. I've fixed them and the fix will be available with the next internal build and later in the release. I've also updated your Telerik points for the find.

Regards,
Kamen Bundev
Telerik