Edit 05/01/2019: One year later nothing was done to fix or improve this addon. As it was my main interaction with Dropmark, I sadly cancelled my account and moved to an alternative.
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Original message: One very annoying pattern with this addon is the post-event validation. Once I click add to dropmark, I should have the window closed by the same operation if the request was valid. I feel like I click twice ok in a row, which is annoying when you save dozens of links a day.