the desktop entry should be in the same binary than the software

Confirmed

Dave have you tried too also delete 'xchat-gnome-common' along with 'xchat-gnome?

pingno, yes I can manually remove it with synaptic, but if the app is not installed (regardless of a common library being installed), the icon should not remain on the main menu.

This issue is still happening in latest release included in Ubuntu Natty Narwhal
---
Ubuntu Bug Squad volunteer triager
http://wiki.ubuntu.com/BugSquad

This bug was fixed in the package xchat-gnome - 1:0.30.0~git20100421.29cc76-1ubuntu1

---------------
xchat-gnome (1:0.30.0~git20100421.29cc76-1ubuntu1) oneiric; urgency=low

  * Merge with Debian unstable, remaining changes: (LP: #773847)
    - debian/control:
      - add Build-Depends on liblaunchpad-integration-dev.
      - xchat-gnome Suggests: xchat-gnome-indicator.
    - debian/patches/02_lpi.patch: add Launchpad integration items to the help
      menu
    - debian/patches/10_xchat-gnome-close-event.patch: add events for window
      close.
    - debian/patches/04_autojoin_ubuntu_chan.patch: add the Ubuntu network
      as default selection and default to autojoining #ubuntu.
    - debian/patches/20_add_gui_focus.patch: implement GUI focus from XChat.
    - debian/patches/51_freenode_default_port_8001.patch: Drop ports 666x
      for FreeNode to workaround a possible DCC exploit.
    - debian/patches/95_apturl-support.patch: support apt://-urls.
    - debian/watch: also look for unstable versions
    - debian/xchat-gnome.gconf-defaults: Set the default enabled plugins,
      indicator, netmonitor, and notifyosd.
  * debian/patches/52_no_zero_width_pixmaps.patch: dropped, applied upstream.
  * debian/patches/98_ice_depends_for_eggsmclient.patch: replaced by
    01_link_libice.patch.
  * debian/control: remove duplicate entry in Build-Depends for intltool.
  * debian/xchat-gnome.install: also install the xchat-gnome.desktop file from
    /usr/share/applications in xchat-gnome rather than xchat-gnome-common.
    (LP: #374686)
  * debian/rules: update the xchat-gnome-common binary-install target to not
    keep a duplicate copy of the xchat-gnome.desktop file.

xchat-gnome (1:0.30.0~git20100421.29cc76-1) unstable; urgency=low

  * New upstream git snapshot.
    + Correctly links to libm and libX11. Closes: #556693.
  * Switch to 3.0 source format.
  * Use autogen.sh, build-depend on the autotools.
  * Update build-dependencies.
  * Drop all patches, they are included now.
  * 01_link_libice.patch: new patch. Correctly link to libICE.
  * Fix long description.
  * 02_libnotify_compat.patch: new patch. Support libnotify 0.5
    correctly.
  * 03_dcc_window.patch: new patch. Don’t set the DCC window visible
    upon startup.
 -- Mathieu Trudel-Lapierre <email address hidden> Tue, 05 Jul 2011 12:27:58 -0400