Dimensions extension crashes when used on blank document

[David Hicks]

Inkscape versions tested: Inkscape SVN 20006
Test platform: Gentoo Linux ~amd64 with gcc-4.3.2, python-2.5.2, gnome-2.24.0, gtk+-2.14.3 and glib-2.18.1

Steps to reproduce:
1. Create new document
2. Effects -> Visualize path -> Dimensions...
3. Apply

Traceback (most recent call last):
  File "/usr/share/inkscape/extensions/dimension.py", line 143, in <module>
    e.affect()
  File "/usr/share/inkscape/extensions/inkex.py", line 172, in affect
    self.effect()
  File "/usr/share/inkscape/extensions/dimension.py", line 97, in effect
    sys.exit(_('Unable to process this object. Try changing it into a path first.'))
NameError: global name '_' is not defined

[Alvin Penner (apenner)]

this is one of those Effects that requires you to first draw, and select, an object before applying the Effect

[David Hicks (dhx)]

Correct. However this effect should either show the user a message explaining that problem (as is the case with Effects -> Modify path -> Envelope), not be enabled in the menu when it can't be used or just do nothing as is the case with a lot of other effects.

[Alvin Penner (apenner)]

fixed in svn 20022.
this was a regression from past behaviour; the new code will now be consistent with Inkscape 0.46