* Extension point for metamodel extension authorization

	- extension would identify metamodel URI as a metamodel that can have extension properties defined
	- ExtensionPlugin should load these
	- ExtensionPlugin should have accessor method for these

* Create model extension definition registry view

	- Shows what the MED registry looks like
	- Since there is an editor for MEDs this view does not need to show the complete MED. Maybe all that is needed is a table with the namespace prefix, namespace URI, metamodel URI, version, and description is all that is needed.
	- Add MED Action
		-- always enabled
		-- choice to either (1) start new model extension definition wizard (see below), (2) add existing workspace MXD file, or (3) add non-workspace file (adds to workspace and to registry)
	- Delete MED Action (Refactor)
		-- enabled by single selection
		-- deletes MED from registry but NOT from workspace (could offer choice to delete file also)
		-- warn user of implications and gives user choice of removing MED from models and from model object properties
	- Edit/Open MED Action (Refactor)
		-- enabled by single selection
		-- opens MXD editor for selected MED
		-- also double-click on MED should open MXD editor
		-- give user choice of changing MED in models and removing/changing model object properties if necessary
	- Importer Action (not needed)
		-- use Eclipse file importer or the Add action
	- Exporter Action (not needed)
		-- just use the Eclipse file exporter
	- Action to find MED References
		-- enabled on single selection of MED
		-- is there an issue with opening each and every model in the workspace
		-- references should be shown in search results view (reuse the model object search results)
	- Only 1 version of MED allowed in registry

* New model extension definition wizard

	- Page 1: workspace path (project path and name), namespace prefix (unique to registry), namespace URI (unique to registry)
	- Finish: open MXD editor

* MXD Eclipse editor

	- tied to a resource (*.mxd file)
	- check readonly flag
	- maybe a tabbed editor (Info, Properties, and Source)
	- inform user of implications of changing MED
	- outline view support (tree)
	- should saving the new MXD editor add to the registry or should there be "Add to registry" button?
	- Issue: internationalization

* Model MED management

	- model resource context menu action
	- ability to apply/store applicable MEDs in model or remove MEDs from model
	- option in dialog to extract model MED to registry (just need path from user)
	- or dialog saying there are no MEDs saved in the model and none that can be applied based on the metamodel URI
	- tell user removing a MED will also remove all associated model object extension properties
	- indicate if MEDs stored in model are not registered or if the versions are different

* Validation
	- Warning: MED in model is not registered. Quick Fix: Add MED to registry. Quick Fix: Remove MED from model.
	- Warning: MED in model is registered but is a different version. Quick Fix: Update registry to model MED version. Quick Fix: Update model to registry MED version.
	- Warning: Model object property does not have a registered MED. Quick Fix: Remove property from model object.
	- Warning: Model object property does not exist in registered MED. Quick Fix: Remove property from model object.
	- Error: MED namespace prefix already exists
	- Error: MED namespace prefix is empty or has illegal characters
	- Error: MED namespace URI already exists
	- Error: MED namespace URI is empty or has illegal characters
	- Error: MED no metamodel extended
	- Error: MED no metaclasses extended
	- Error: MED no properties for extended metaclass
	- Error: MED property ID already exists
	- Error: MED property ID is empty or has illegal characters
	- Error: MED extended metamodel URI is not allowed to be extended
	- probably lots more errors. but might be able to just parse the MXD file and if exception use that as the error message.

* Question: Should we show model's MEDs in explorer tree?

* Task: Update Wiki article on model extension framework

* Task: Include JIRA mockups