Fix profit indicator
Fix profit indicator

The stage was receiving multiple mouse events per click, likely due to
insufficient cleanup before it's replaced. Explicitly unregistering
the event listeners should prevent this problem.

Also, explicitly discarding children to reduce the severity of the
problem in case the stage is somehow leaking.

jvamosi/Diversibee,cgmb/Diversibee,jvamosi/Diversibee,cgmb/Diversibee