ControlContext :: currentProperty - Get property handle for currently selected line

Usually, the function returns property handle that acts as data source for the control, i.e. the same as property(). In case of trees or multiple region lists, however, several data sources are referenced by the control. For these controls, the function returns the property handle for the region currently active. This is, usually, the region containing the line currently selected. Several event handlers also return the property handle currently accessed (e.g. doAfterDataSet() returns the property handle for the line currently read or doAfterInsert() returns the property handle for the region, where an item has been inserted).