Mission lightposts don't work on URLs containing colons

I am trying to add the URL http://en.wikipedia.org/wiki/Image:Lu... to a mission; it lets me lightpost it from the toolbar, but I can't add that lightpost to a mission. I suspect this is because the URL contains a colon, and therefore that it would affect all Wikipedia system pages and Wikimedia/Commons pages as well.
 
silly I’m not really surprised
Inappropriate?
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