To your questions:
1. Locked columns and detail template is not supported as mentioned here. The reason - detail template is a single row, while locked columns are rendered in separate table and there ins't "correct" way of splitting detail template between both tables. Hence it is not supported.
2. Detail template is initialized on first expand of the master row. It always has class name `k-detail-row`. You can use to find detail rows and manually hide them. It isn't supported by the widget to hide/show conditionally detail templates.
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