I have been having a hard time explaining this to the Google Apps support team. I originally contacted them because I had a lot of labels with leading special characters that I use to affect their sort order. For example, I have a "?Bulk" label grouped together with other "?Bulk/sublabels" (e.g., "?Bulk/Facebook"). The leading question mark prevents them from showing up in the middle of other labels I have that start with "B". Moreover, using leading special characters lets me put certain important labels at the top of my list where they are easy to see and access.
Now, the search bar at the top of the GMail web interface doesn't have much problem with this. It will match such labels regardless of whether I include the leading special character:
Note that it's not just finding partial matches in the middle of a label. If you drop the first alphanumeric character after the special characters, you get no matches:
Now, you would expect the "Move To" and "Copy To" quick searches to behave the same way. At first, it seems like they do. They'll do partial matches from the front of the label if you include the special character:
But if you drop the special character, you're doomed.
Pretty annoying, huh? See, "Move To" and "Copy To" are using some special grammar to extract information from the list of labels. Apparently this grammar is overly simple. Now, I might be able to live with that if it wasn't the case that GMail Search knows how to get labels right. In fact, Gmail Search can even handle nested labels with leading special characters. Check it out:
See? It was able to recognize that the "/" in big version of the label name separated parent from child label (which actually can be a problem if you're not intending to use nested labels). It then looks for matches at the start of the sublabel, which is in the middle of the big label shown. Pretty cool. Moreover, if you drop the leading alphanumeric character, the match fails:
Now, apparently "Move To" and "Copy To" have some of this matching behavior. That is, they'll properly chop the label into parent and child and look for matches in just the child part:
Unfortunately, you need the special character for the match to work:
So, again, for some reason GMail has developed the quick search for "Move To" and "Copy To" independently from GMail Search in general. Maybe this was an optimization, but it seems like it wouldn't be too slow to call out to GMail Search to find these labels. Then everything would be consistent.
Now, I tried explaining this to the Google Apps support team initially. You know what they told me? That "Gmail Search" doesn't do partial matches, and so it's the expected behavior. Can you believe they actually had the nerve to forward me to a GMail Search page when the real problem is that "Move To" and "Copy To" are in fact acting DIFFERENTLY than GMail Search? IF ONLY the issue was with GMail Search; I could live with that.
Well, Thunderbird gets it right. I guess that's a nice workaround.