By default, the AllowToggleSelectKey property is exCTRLKey, which indicates that the user can unselect/select an element by pressing the left mouse button and keeping the CTRL key down. The AllowToggleSelectKey property indicates the key to be used so the user can toggle a selected element. Set the AllowToggleSelectKey property on exDisallow to prevent selecting elements when clicking them ( while keeping the CTRL key ). The AllowSelectObject property indicates the keys combination to allow user selecting new elements. The SelectionChanged event occurs once a new element is selected or unselected. The Selectable property of the Element object indicates whether the element is selectable or un-selectable. The AllowSelectNothing property indicates whether the selection is cleared once the user clicks any empty area on the surface. The AllowSelectObjectRect property specifies the keys combination so the user can select the elements from the dragging rectangle. The SelectAll method selects all elements in the chart. Use the UnselectAll method to unselect all elements on the surface. The SingleSel property specifies whether the surface allows selecting one or multiple elements. The SelCount property counts the number of selected elements. The SelElement property returns the selected element based on its index in the selected elements collection. The Selection property sets or gets a safe array of selected elements.