When you’re moving posts, and the only option is to move it to an existing topic (for example, when you’re moving the only post in a topic), it would be great if the search input was focussed by default:
This is quite common on the forum I administer when people make duplicate suggestions in our “suggestions” category. 
It’s a matter of only a few seconds, but ergonomically it makes sense to me. 
It’d also be great if, when there’s only one matching topic, that were selected by default, too. Perhaps only when the ID is entered, though?
Er what? This is never the case. You can always move a post to
Hmm… Well, I’m definitely seeing this on my site:
This is from a topic that only has one post in it, and I’m moving that post only.
Hmm. I’m not sure why you would only see that option.
I have also selected one post in a topic that contains only one post, and I see…
Any thoughts here @techAPJ?
Related?
Oh interesting possibly. Did you press “select all” instead of manually selecting the one post in the topic @barryvan
I got that behavior just now by selecting the OP of a topic with no replies. If I hadn’t intentionally tried it I would not have known. Any time I have wanted to “move” an entire topic to a new topic, I have always recategorized it using the topic title edit.
It seems to happen regardless of whether I use the “select all” option or choose the post individually.
I figured this was intentional – as @Mittineague notes, there’s not much point in moving a single post topic into a new topic.
Oh, OK. My bad. So this is “normal” if you select the first post in a topic with no replies. 
That being the case, do you think there’s any validity in the original suggestions? That is, in this case, focus the search input automatically, and, if you enter an ID, automatically select that item?
It’s such a rare case I’m not sure it’s worth a lot of engineering time.
I experimented locally and was able to add this feature fairly easily via:
https://github.com/discourse/discourse/commit/4786b7ff812ae2e2563ec10df6cf4ba46645b49e
