Tree expand/collapse issue in NatTable(0.9->1.0)

I was facing tree expand/collapse issue in NatTable after migrating from 0.9 to 1.0 version.  I could not even expand or collapse a tree after migration, it was disabled completely so we can’t even see the children of a tree.

This can be resolved by configuring CellPainterMouseEventMatcher with GridRegion.BODY  instead of  TreeLayer.TREE_COLUMN_CELL

If you are facing the same issue, this would be useful tip.