Hi Jason,
Greetings from Syncfusion support.
We have validated your requirement in the Dropdown Tree
component. Currently, we don’t have support to add a new item in the Dropdown
Tree while searching if it is not available in the tree. However, this exact
feature is available in our EJ1 AutoComplete control. Please check the details
at the below link.
https://help.syncfusion.com/api/angular/ejautocomplete#members:allowaddnew
Please confirm whether this control is suitable for you. If
not, please revert us back to us for further assistance.
Regards,
Indhumathy L