Another YES for this functionality.
A thread has been reported, it's a duplicate or I want to merge it into another. I have too....
1. Click and open the thread from the report (not functionality to select the thread from the /report/ URL!)
2. Exit the thread and go back to it's forum.
3. Scan the forum titles to find the thread that I was in from step 1, and tick to select it.
4. Use search to find the matching/target thread that I want to merge it into.
5. From search, click the thread to open (because, like Report, I cannot select the thread from search results)
6. Exit the thread and go back to it's forum.
7. Scan the forum titles to find the thread that I was in from step 1, and tick to select it and perform the merge.
7 steps, very manual and intensive, just to merge the threads together.
Please make this a much easier and friendly user experience in XF!