The original goal of the action system refactoring was that the central action registry would read the action definition xml files (*.action) and create actions and assign them to the central action collection. Nowhere in the code would we actually create actions manually anymore, just fetch them by name when we'd need to connect slots to them.

That somehow hasn't happened yet, and that means that we still have bugs like

https://bugs.kde.org/show_bug.cgi?id=370720
https://bugs.kde.org/show_bug.cgi?id=385030
https://bugs.kde.org/show_bug.cgi?id=365222

Where, because tools are only created once a canvas is created, the actions that are created in the tool's constructor aren't available before a document has been created. If you'd add that action to the toolbar, then create a second document, the action won't be active because it's per-view.