Fix ClearColumns() to release associations between m_OutlineView and native Cocoa control when re-creating the latter. Previously it only created a new association, but left the old one with no-deleted native control in the map. Fixes #17485.
Fix ClearColumns() to release associations between m_OutlineView and native Cocoa control when re-creating the latter. Previously it only created a new association, but left the old one with no-deleted native control in the map. Fixes #17485.