Hello Johan,

I also consider this feature a very useful one. Since you are the creator of the post you are subscribed and will receive email notifications when its status changes. This is the best way to keep in track with the progress of the feature as once we know which release will contain its implementation, we will update its status in the feedback portal and you will be notified via email accordingly.

In the meantime, you can use the approach suggested in the knowledge base article you linked. If you want to include a checkbox in a header template to handle select all functionality, an important point to consider is that at this stage this approach will indeed not update the selected items in the popup as you correctly mentioned. To cover this scenario, we have another feature request for refreshing the popup event that you might be interested in - Refresh Popup Method. You may vote for it and follow it to be notified for its progress as well.

Regards,
Nadezhda Tacheva
Progress Telerik