Spread.Sheets supports built-in context menus, the context menu can be opened by right-clicking on the Spread.Sheets instance. The contents of this menu depend on which area of the workbook is clicked.
The context menu provides the following abilities:
You can use the spread.options.allowContextMenu option to control whether to show the built-in context menu or not.
var spread = GC.Spread.Sheets.findControl(document.getElementById('ss'));
spread.options.allowContextMenu = false;