D Haley reports in the Debian BTS[0]:

The following sequence of commands can produce a bug whereby a tag, such as "release version" will instead only show "version" in the tag view. This appears to be a regression, as this previously worked in earlier versions of hg view.

Here is a sesion reproducing the bug:

$ hg init f
$ cd f
$ echo a > file
$ hg add file
$ hg commit -u "me" -m "commitMesg"
$ echo "otherstuff" > file
$ hg commit -u "me" -m "yacm"
$ hg tag -u me -r 1 -m "commit tag" "Some Tag Here"
$ hg --config extensions.hgk= view

Instead of "Some Tag Here", i simply see "Here" in the tree display. The contents of .hgtags appears to be correct, and so does the output from hg tags.

I think *maybe* that it might be related to this change. Ive rarely used tcl.:
http://www.selenic.com/pipermail/mercurial-devel/2013-March/049582.html

[0] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=725904

hgview is a separate project whose bug tracker lives here: <https://www.logilab.org/project/hgview>.

This is not hgview, it's "hg view".  It's part of hgk, which is shipped with mercurial.

Setting this to confirmed. Also setting it to wish:

http://mercurial.selenic.com/wiki/UnlovedFeatures

I've prepared a patch fixing this issue; sending it in a moment.

Fixed by http://selenic.com/repo/hg/rev/970394b6bd97
Andrew Shadura <andrew@shadura.me>
hgk: fix tag list parser (issue4101)

As tags may have embedded spaces, and "hg tags" command doesn't escape them,
the output of the command doesn't make a well-formed list, so we can't just
iterate over it. Instead, apply a simple regexp to transform it to a list
which we actually use. Line boundary matching should be enabled.

(please test the fix)