XlsFile.ActiveSheetForActiveWindow Property
Gets or sets the active sheet for the ExcelFile.ActiveWindow. Note that this won't change the active sheet for FlexCel when you enter a value, you still need to call ExcelFile.ActiveSheet for that. This property will only change the sheet that is active in that window when you open the file in Excel. Setting this property will also unselect the other sheets. If you want to select multiple sheets, make sure to select them *after* setting the ActiveSheetForActiveWindow.
Syntax
Namespace: FlexCel.XlsAdapter
public override Int32 ActiveSheetForActiveWindow { get; set; }