maybe this is intentional as it seems there are situations where you want the interactivity work outside of design mode? storyboards are problematic as they make designing challenging and there is no way to prevent it or stop it that I can find. suggestion would be to not play storyboards in design mode outside of the dopesheet editor, or have "execute in design mode" flags on events.

This is a known issue that we haven't handled yet because as you mentioned is not trivial. Sometimes you may want the triggers to invoke the actions, and sometimes it could be problematic (like with animations).

To stop the Storyboard from playing the only workaround right now is going to the Animation tab (Ctrl+4), select the playing animation and select "No storyboard applied" again.

thank you for the workaround, as a quick fix i would suggest disabling storyboards entirely as there is not a use case for playing animations at design time when not editing the animation, unless it is other storyboards triggering while editing a animation.