Bug 87111 [Dialogs] Feature: add general-purpose page change notification for dialogs
New dynamic help pane attaches itself to all the dialogs that JFace provides. Some of these dialogs manage multiple pages but dynamic help has no way of registering for page change notification. Examples of dialogs that exhibit this behaviour are WizardDialog, PreferenceDialog, LaunchConfigurationDialog (in Debug), PropertiesDialog etc. Attached is the code for the following proposed enhancement: 1) A new interface 'IBaseDialogPage' that interfaces like IDialogPage and ILaunchConfigurationTab can extend 2) A class PageChangedEvent for page change notification 3) A new interface 'IPageChangeProvider' 4) A new interface 'IPageChangedListener' In the attached patch, WizardDialog and PreferenceDialog implement IPageChangeProvider and notify page changed listeners whenever current page changes. This allows dynamic help to update its content and show the relevant help for the currently selected page. Since IBaseDialogPage is now a base interface for IDialogPage, two methods (getTitle() and getControl()) are moved up from IDialogPage. This is consistent with ILaunchConfigurationTab and does not clash with any existing method.
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceDialog.java
return composite;
	}
	/**
	 * Create the pageArea in the composite.
	 * @param composite
	 * @param layout
	 */
	private void createPageArea(Composite composite, GridLayout layout) {
		Composite pageAreaComposite = new Composite(composite, SWT.NONE);
		pageAreaComposite.setLayoutData(new GridData(GridData.FILL_BOTH));
		GridLayout pageAreaLayout = new GridLayout();
		layout.marginHeight = 0;
		layout.marginWidth = 10;
		pageAreaComposite.setLayout(pageAreaLayout);
		
		
		pageContainer = createPageContainer(pageAreaComposite);
		pageContainer.setLayoutData(new GridData(GridData.FILL_BOTH));
		
		Label separator = new Label(pageAreaComposite, SWT.HORIZONTAL | SWT.SEPARATOR);
		GridData gd = new GridData(GridData.FILL_HORIZONTAL);
		separator.setLayoutData(gd);
	}
	/**
	 * Create the sash with right control on the right. Note 
	 * that this method assumes GridData for the layout data
	 * of the rightControl.
	 * @param composite
	 * @param rightControl
	 * @return Sash