I've been bugged by this all day... Anyway, here we go. When turning an object to insensitive via the item properties menu, there's a line added in the xml:
sodipodi:insensitive = "true" formally that was sodipodi:insensitive = "1" it seems, since I have a few objects I created with inkscape not long ago, that have that tag. Anyway, setting the value to either "false" or "0" in the xml editor doesn't do anything. Checking sensitive in the item properties dialog again, deletes the whole line. This can of course be done in the xml editor as well, but it's a wierd behaviour, that the value setting doesn't do anything. It also brings me to another point. When you select an attribute and press [del] the whole object is deleted. Rather than that the specific attribute should be deleted, I think. And when selecting a undeletable item, the "delete attribute" should be insensitive.
What I also found to be very surprising, is, that I can select items within a insensitive group via ctrl+click, but am not able to select the insensitive item via shift+click or alt+click and then change it back to sensitive via the right-click menu, but as it seems to me have to use the xml editor to select it, and then either directly delete the insensitive attribute or use the item properties dialog to do so.
David