Mark; further to the above fix I have had a cautious "play" with the (potential) new capability and would offer the observation below.
With nothing "selected" the function buttons are effectively greyed out, but it isn't all that clear when something has been selected for action; the change in the appearance of the 4 new buttons is fairly minimal.
Would it be possible for the buttons to actually change colour when a selection is made, with the Delete button being red to minimise the risk of mishaps?* Different colours for the other three (Merge, Hashtags and More) might also be helpful.
* Being cautious I didn't put this to the test but can we assume that the Delete function requires confirmation before deletion actually occurs, much as it does now?