Greetings from Syncfusion Support.
Currently we don’t have the support to perform frozen columns/rows in treegrid. We will consider your requesting as “Frozen columns/rows support in TreeGrid” feature. We are always trying to make our products better and feature requests like yours are a key part of our product growth efforts. So this feature will be included in our 2019 Volume 3 release which is expected to be rolled out in the month end of September 2019.
You can track the current status of your request, review the resolution timeline and contact us for any further inquiries through this link.
Note: To view the above feedback, kindly login into your account. Currently the feedback request is in review, so you can able to view the feedback request once its reviewed.