Event fired before drop down is opened for a specific column summary. Return false in order to cancel opening the drop down. Function takes arguments evt and ui. Use ui.columnKey to get column key of the column where drop down is opening. Use ui.owner in order to access the igGridSummaries widget object.
Target Platforms: Windows 8.1, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
