Hi Deanna,
Thank you for contacting Syncfusion Support.
We have prepared a sample which tries to meet your requirement.In this sample,we have added flyout to TreeNavigatorItem using FlyoutBase.AttachFlyout attached property and showed that flyout when the item is clicked
Please download the sample from the below link
Sample :
SfTreeNavigatorSampleIf your requirement is different from the sample,please provide more information about your requirement
Regards,
M.Sugapriya