20. A computer-readable storage medium having computer-executable instructions that, when executed on a computer, perform a method comprising: detecting an editing event requesting manipulation of a document; routing the editing event to a first designer; receiving a response from the first designer that indicates whether the editing event was consumed by the first designer; and routing the editing event to a second designer when the response indicates that the editing event was not consumed by the first designer, wherein an order in which the editing event is routed to the first designer and the second designer is based on an order in which the first designer and the second designer were registered with an editor.
20. A computer-readable storage medium having computer-executable instructions that, when executed on a computer, perform a method comprising: detecting an editing event requesting manipulation of a document; routing the editing event to a first designer; receiving a response from the first designer that indicates whether the editing event was consumed by the first designer; and routing the editing event to a second designer when the response indicates that the editing event was not consumed by the first designer, wherein an order in which the editing event is routed to the first designer and the second designer is based on an order in which the first designer and the second designer were registered with an editor. 21. The computer-readable storage medium as recited in claim 20 , further comprising computer-executable instructions to perform a method comprising: receiving an additional response from the second designer that indicates whether the editing event was consumed by the second designer; and processing the editing event if the response from the second designer indicates that the editing event was not consumed by the second designer.