Now that the "Add action" interface allows for multiple actions being added, it seems improper that the action selection mechanism is a dropdown. Dropdowns suggest that only one of the following actions is appropriate to choose and also require more clicks.

Potential solution: Turn "Add action" dialogue into a bank of buttons

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|    Assign/claim: [  tel (Joseph Abrahamson)                                                   ]  (x)                 |
|    Change status: Resolved                                                                       (x)                 |

As a bank of buttons it's more clear that you can just click them over and over to get more actions in the listing. It might require a set of good iconography (which would probably be a much larger project since you'd want to make the iconography consistent throughout the interface) but could suffice with just text.