Treemap tooltips broken when using boost

[cvasseng]

Expected behaviour

Working tooltips when boosting treemaps.

Actual behaviour

Hovering the node titles, which should trigger the tooltip, triggers an exception instead.

Problem seems to be that the tooltip code assumes that SVG groups exists, which is not the case when boosting.

Live demo with steps to reproduce

http://jsfiddle.net/gh/get/library/pure/highcharts/highcharts/tree/samples/highcharts/boost/treemap/

Affected browser(s)

All.