10. The system as recited in claim 7 , wherein the event routing controller further provides an event identifier uniquely identifying the editing event.
7. A system, comprising: a processor; and one or more computer-readable storage media having computer-executable instructions stored thereon that, when executed by the processor, implement: an extensible editor that processes editing events requesting manipulation of a document, the extensible editor having an event routing controller and a default event handler; and a first extension and a second extension coupled with the extensible editor for processing the editing events, wherein the event routing controller provides an editing event received by the extensible editor to the first extension prior to providing the editing event to be processed by the default event handler, wherein the event routing controller provides the editing event to the second extension prior to providing the editing event to be processed by the default event handler when the first extension does not consume the editing event, and wherein an order in which the editing event is routed to the first extension and the second extension is based on an order in which the first extension and the second extension were registered with the extensible editor.