Allow injecting a tooltip into the document body directly
Allows using highcharts within more complex stacking contexts, and offers a much cleaner solution to issues like http://stackoverflow.com/questions/18658043/highcharts-pie-tooltip-cuts-off, http://stackoverflow.com/questions/10734746/highcharts-tooltip-overflow-is-hidden, http://stackoverflow.com/questions/31415313/force-highcharts-to-display-tooltip-outside-of-div-container, http://stackoverflow.com/questions/20556824/highcharts-tooltip-z-index, http://stackoverflow.com/questions/15130311/highcharts-labels-visible-over-tooltip, etc.
Boris Cherny
shared this idea
I think this study addresses the problem:
http://jsfiddle.net/gh/get/jquery/1.7.2/highcharts/highcharts/tree/master/samples/highcharts/studies/tooltip-outside-box/
We are considering making this a part of the core. Does it resolve your problem?