This add-on does not have any dialogs, nor does it open boxes to bookmark stuff. The extension only adds context menu entries to your bookmarks and bookmark folders, which opens the bookmark (or the tabs in the bookmarked folder) in new (container) tabs. Do you have any other add-ons?

Side note, the IceDragon browser has not been updated for over a year. Outdated browsers are full of unpatched security issues, and should therefore not be used. Your security and user data is at risk when you continue to use IceDragon.