Hi,

I would like to put forward a feature request to allow the panel bar items to be mounted when the panel bar itself mounts, irrelevant of whether it has been opened or not.

I'm looking for something like the keepItemsMounted property http://www.telerik.com/kendo-react-ui/components/layout/panelbar/mounted-items, but without the condition that a panel bar has to be opened at least once for them to stay mounted.