Description of problem:
Evolution chrashes if you use the Attachment Bar in the composer and right click
to add attachment

Version-Release number of selected component (if applicable):
evolution-webcal-2.4.1-3.2
evolution-data-server-1.5.90-2.2
evolution-data-server-debuginfo-1.5.90-2.2
evolution-webcal-debuginfo-2.4.1-3.2
evolution-debuginfo-2.5.90-2.1
evolution-2.5.90-2.1


How reproducible:
always

Steps to Reproduce:
1. new mail message (Ctrl+N)
2. click on "Show attachment bar"
3. right click on attachment area 
  
Actual results:
crash

Expected results:
adding attachment

Additional info:
Content of console after starting evolution:
$ LC_ALL=POSIX evolution
CalDAV Eplugin starting up ...

(evolution:7567): evolution-mail-WARNING **: ignored this junk plugin: not
enabled or we have already loaded one

(evolution:7567): e-utils-WARNING **: Plugin 'Spamassassin junk plugin' failed
to load hook 'org.gnome.evolution.mail.junk:1.0'

(evolution:7567): camel-WARNING **: camel_exception_get_id called with NULL
parameter.
libnm_glib_get_nm_state(): org.freedesktop.DBus.Error.ServiceUnknown raised:
 The name org.freedesktop.NetworkManager was not provided by any .service files

libnm_glib_get_nm_state(): org.freedesktop.DBus.Error.ServiceUnknown raised:
 The name org.freedesktop.NetworkManager was not provided by any .service files


(evolution:7567): Bonobo-WARNING **: Can't find
'/usr/lib/evolution/2.6/plugins/org-gnome-mail-to-task.xml' to load ui from

(evolution:7567): camel-WARNING **: camel_exception_get_id called with NULL
parameter.

(evolution:7567): camel-WARNING **: camel_exception_get_id called with NULL
parameter.
Variable "id" is not available.
Variable "e" is not available.
Variable "resultvar" is not available.
Variable "e" is not available.
Variable "e" is not available.
Variable "e" is not available.
Variable "e" is not available.
Variable "e" is not available.
Variable "resultvar" is not available.
Variable "resultvar" is not available.
Variable "pid" is not available.