The "Bookmark current tab" interface, when accessed from the menu in the upper left of the window, is a vast improvement over the "Bookmark tab" interface encountered when I right-click on a tab. However, the menu-accessed version does not support "Bookmark SELECTED TABS". This should be fixed. The old interface should be done away with entirely.
Further, this whole process could be replaced by simply supporting drag-and-drop from the tab bar (and tabs in the Tree Style Tab add-on that I use) into the Manage Bookmarks window, which has a fantastic interface! That window could be invoked whenever a user wants to bookmark any tab. That would be the ultimate solution.