During the LayoutStartChaning event, you can call the CancelLayoutChanging method to cancel the specified operation. Calling the CancelLayoutChanging method anywhere else, has no effect. 

The operations being signaled by the LayoutStartChanging / LayoutEndChanging events are:

• exSurfaceMove, the user scrolls or moves the surface. The AllowMoveSurface property specifies the keys combination to allow user to move / scroll the surface.
• exSurfaceZoom, the user magnifies or shrinks the surface. The AllowZoomSurface property specifies the keys combination to allow user to zoom the surface.
• exSurfaceHome, the user clicks the Home button on the control's toolbar, so the surface is restored to original position. The Home method has the same effect.
• exResizeObject, the user resizes the object. The AllowResizeObject property specifies the keys combination to allow user to resize the object.
• exMoveObject, the user moves the object. The AllowMoveObject property specifies the keys combination to allow user to move the object.
• exSelectObject, the user clicks the object to get it selected. The AllowSelectObject property specifies the keys combination to allow user to select the object.
• exSelectNothing, the user clicks an empty zone of the surface. The AllowSelectNothing property specifies the keys combination to allow user to select nothing on the surface.
• exCreateObject, the user creates an element on the surface. The AllowCreateObject property specifies the keys combination to allow user to create elements on the surface.
• exEditObject, the user edits the element's caption.
• exLinkObjects, the user creates an element on the surface. The AllowLinkObjects property specifies the keys combination to allow user to link elements on the surface.