Steps to reproduce:
This bug is probably directly related to #290, or some closely related part of the events handling. Events on each point should be destroyed when the point is destroyed. Work on #290 first, then come back to this one.
In prototype-adapter line 124 a new effect is created for each attribute, it will then connect it self to the el._highcharts_animation property. This way, the last one is overwriting the handle to all previous animations on the same element. Also the fx local variable is just left dangling.
Later on in stop(), only the last one is canceled, leaving all other animations running on the destroyed chart. I think this is causing the error messages.
References to effects in prototype adapter are kept until they are fi…
…nished or canceled. Closes #291