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:

• xSurfaceMove, 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.
• exResizeElement, the user resizes the object. The AllowResizeElement property specifies the keys combination to allow user to resize the object.
• exMoveElement, the user moves the object. The AllowMoveElement 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.
• exCreateElement, the user creates an element on the surface. The AllowCreateElement property specifies the keys combination to allow user to create elements on the surface.
• exEditElement, the user edits the element's caption. The Edit method edits the element.
• 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.
• exDesignMode, The user changes the surface's design mode. The exDesignMode operation occurs, when the user selects a new design-mode, from the control's toolbar. The DesignModes property specifies the modes to be displayed on the Design toolbar. The DesignMode property specifies the control's design mode. Depending on the design-mode, the user can select elements, pools or none.
• exCreatePool, The user creates pools on the surface. The AllowCreatePool property specifies the keys combination to allow user to create pools on the surface.
• exResizePool, The user resizes the pool from the surface. The AllowResizePool property specifies the keys combination to allow user to resize the pool.
• exMovePool, The user moves the pool from the surface. The AllowMovePool property specifies the keys combination to allow user to move the pool.
• exResizeLane, The user resizes the lane of the pool. The AllowResizePoolHeader property specifies the keys combination to allow user to resize the header of the pool.
• exMoveLane, The user moves/changes the position of the lane of the pool. The AllowMoveLane property specifies the keys combination to allow user to moves/changes the position the lane.
• exContextMenuObject, The object's context menu is running. The user right-clicks an object on the surface, and it's context menu is shown. Use the AllowContextMenu property to specify the combination of keys that allows the user to open the object's context menu.  Use the ContextMenu property to provide a custom context menu for the objects on the surface.
• exActionContextMenuObject, An item from object's context menu is executing. Use the AllowContextMenu property to specify the combination of keys that allows the user to open the object's context menu.  Use the ContextMenu property to provide a custom context menu for the objects on the surface. The ActionContextMenu event notifies your application once an action occurs within the object's context menu.