Bug in MIME type detection - nautilus or vfs?

[Daniel Leidert <daniel leidert spam gmx net>]

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Hello,

There is a bug in the MIME type detection in nautilus. To show what I
mean: I have a directory, where all my bluefish-projects files resist.
The application/bluefish-project MIME type is defined via
shared-mime-info database.

[1] shows, what I see, when I open the directory in nautilus. It seems,
that the MIME type is detected correctly.

[2] But then I make a right-click on a .bfproject file and the icon
changes and the MIME-type is detected as text/plain.

[3] The "Open with" menu shows text-editors and the bluefish.

[4] The "Open with" tab in properties only shows text editors.

The bug is completely reproducible with a lot of MIME types (e.g. almost
all chemical/* MIME types do not work any longer). Is this a bug inside
gnome-vfs or nautilus?

[1] http://debian.wgdd.de/temp/nautilus/nautilus_bfproject_dir.png
[2] http://debian.wgdd.de/temp/nautilus/nautilus_bfproject_dir_mime-type.png
[3] http://debian.wgdd.de/temp/nautilus/nautilus_bfproject_dir_openwith.png
[4] http://debian.wgdd.de/temp/nautilus/nautilus_bfproject_dir_properties.png

My distribution is a Debian Sid with:
nautilus 2.12.2-2
libgnomevfs2-0 2.12.2-3
shared-mime-info 0.16-3

Regards, Daniel