Bug 282875 [UI] Allow parts of models to be rendered
We need to change the rendering protocol to allow a 'createGui' to specify the container it should be created under (in SWT-land this would be a Composite). This is necessary to facilitate unit tests and to allow the ad-hoc rendering of chunks of a model within an arbitrary container (i.e. a Dialog or Wizard). In order to do this we'll have to make an API change to the PartFactory's 'createWidget' so that it will get the parent container as a parameter. In order to 'upgrade' an existing PartFactory you would simply replace the code you're currently using to find the correct container with the new parameter's value.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/workbench/ui/renderers/PartFactory.java
protected IEclipseContext getContextForParent(MPart<?> part) {
		MPart<?> parent = part.getParent();
		while (parent != null) {
			if (parent.getContext() != null) {
				return parent.getContext();
			}
			parent = parent.getParent();
		}
		return context;
	}
	/**
	 * Return a context for this part.
	 * 
	 * @param part
	 *            the part to start searching from
	 * @return the closest context, or global context if none in the hierarchy
	 */
	protected IEclipseContext getContext(MPart<?> part) {
		if (part.getContext() != null) {
			return part.getContext();
		}
		return getContextForParent(part);
	}
	protected IEclipseContext getToplevelContext(MPart<?> part) {
		IEclipseContext result = null;
		if (part.getParent() != null) {
			result = getToplevelContext(part.getParent());
		}
		if (result == null) {
			result = part.getContext();