Comment 6 for bug 443229

I can reproduce it with the example in bug #427540 <http://launchpadlibrarian.net/31617709/%5C192.168.10.12%5Cgordon%5Cwork%5C2007-ft2%5Cpower-distribution%5Celectrodes-and-clamps-channel-and-forehearth%5C090909-troubleshooting-inkscape-and-pdfs%5Cone-saved-after-opening-original-pdf.svg> :

enter the groups with double-click until you can select an illustration (rather: it's a grouped rectangle with a mask containing the image in the defs section) and delete the object (rectangle) that looks like the image itself.

Result: the image is gone (on canvas) but the embedded bitmap stays in the defs mask definition.
expected: original embedded image in the mask gets removed as well.

Mask:
<mask
       maskUnits="userSpaceOnUse"
       x="0"
       y="0"
       width="1"
       height="1"
       id="mask159"><image
         width="1"
         height="1"
         xlink:href="data:image/png;base64, (…snipped…)"
         id="image161" /></mask>

Illustration:
<g
             id="g157"
             transform="matrix(188.872,0,0,117.055,300.167,240.278)"><rect
               x="0"
               y="0"
               width="1"
               height="1"
               transform="matrix(1,0,0,-1,0,1)"
               style="fill:#000000;fill-opacity:1;fill-rule:nonzero"
               mask="url(#mask159)"
               id="rect163" /></g>