This applies to the 'associate task' dialog on a differential revisions and diffusion commits:
Typing enter in the autocomplete field closes the dialog/submits the form, without selecting any tasks. This is true even if you have typed enough so that the completion matches a single task.
You shouldn't have to click the "select" button when a single task is selected via keyboard input.
The proposed implementation feels a little bit too magical to me (enter closes the dialog unless exactly one task is shown in the search results, in which case it attaches that task and closes the dialog), and you also need the mouse to get into this dialog, and there's no way to accomplish any other task it handles (removing edges, adding more than one edge, etc) without using the mouse, but I think we can definitely improve the usability of this dialog.
just disabling Enter would be enough, Its hardcoded inside my brain that when I search for something I hit Enter to see it. I've lost large lists of carefully selected dependencies because of this nasty habit multiple times :(