From my side, I suppose it's the same than you: for both the bookmarks and feeds boxes, I can click on "configure", but then it's impossible to enter any text in the "bookmark alias" and "bookmark URL", for instance. The cursor shape becomes the one for a text area, but not for an entry field.
That's a pity, because this plugin would be really great, if this bug (if it is one) could be fixed.
Unfortunately, the author of this plugin can't work currently on that (entering in a "social hibernation", regarding his twitter account: https://twitter.com/#!/imath). But somebody else may find a clue to fix this issue ?