tm-new-tiddler is a message the core already handles, so the button needs no catcher of its own.

• message is set to tm-new-tiddler
• param names a template tiddler, and the new tiddler starts out with that template's fields

This test case carries a TaskTemplate payload tiddler holding tags, status and priority. Open the TaskTemplate tab above to see it.

The message creates a draft and normally opens it for editing. A test case has no story river, so the table lists the drafts instead. Each click adds one row, and the new tiddler takes the next free title because the previous draft still exists.