The behavior in my 1249 MM corresponds to chrisjj's description - using just a : search returns all tracks in the library, using ":" search returns no tracks.

> I use the default Options|Search settings.

Here (assuming newly created user has the defaults) that shows the Observed effect:
[url=http://img529.imageshack.us/my.php?image=13502553.gif][img]http://img529.imageshack.us/img529/6913/13502553.th.gif[/img][/url] [url=http://img529.imageshack.us/my.php?image=61097964.gif][img]http://img529.imageshack.us/img529/4420/61097964.th.gif[/img][/url]

Strange, entering both ":" and : gives me the exact same results: 10537 files in my library.
I use the default Options|Search settings.

1 In quick search enter [b]:[/b]
2 See many matches
3 Enter [b]":"[/b]

Expected: same matches*
Observed: none

* Help: [quote]Search for "Help!" : Finds an exact match (doesn't ignore the special character).[/quote]


EDIT(TC) Tracked at http://www.ventismedia.com/mantis/view.php?id=6830