Bug 6412 API Request - Package selection dialog including pre-reqs
The Java debugger requires the ability to specify a "pacakge to run in" in the snippet editor. To do this, we use the API on JavaUI to create a package selection dialog for a project. However, we need to be able to choose from packages in pre-req projects/jars as well. Currently the API only specifies packages in a single project.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/JavaUI.java
* </p>
	 * <p>
	 * [Issue: SelectionDialogs must be parented. shell must not be null.]
	 * </p>
	 * 
	 * @param parent the parent shell of the dialog to be created
	 * @param context the runnable context used to show progress when the dialog
	 *   is being populated
	 * @param scope the scope that limits which types are included
	 * @param style flags defining the style of the dialog; the only valid values are
	 *   <code>IJavaElementSearchConstants.CONSIDER_BINARIES</code>,
	 *   <code>CONSIDER_EXTERNAL_JARS</code>, or their bitwise OR, or <code>0</code>
	 * @param multipleSelection <code>true</code> if multiple selection is allowed
	 * @param filter the filter
	 * @return a new selection dialog
	 */
	public static SelectionDialog createMainTypeDialog(Shell parent, IRunnableContext context, IJavaSearchScope scope, int style, boolean multipleSelection, String filter) {
		AbstractElementListSelectionDialog dialog= null;
		if (multipleSelection) {
			dialog= new MultiMainTypeSelectionDialog(parent, context, scope, style);
		} else {
			dialog= new MainTypeSelectionDialog(parent, context, scope, style);
		}		
		dialog.setFilter(filter);
		return dialog;
	}
	/**
	 * @see createMainTypeDialog(Shell,IRunnableContext,IJavaSearchScope,int,boolean,String)
	 */
	public static SelectionDialog createMainTypeDialog(Shell parent, IRunnableContext context, IJavaSearchScope scope, int style, boolean multipleSelection) {