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/wizard/WizardDialog.java
getShell().setBounds(getConstrainedShellBounds(size));
    }
    /**
     * Computes the correct dialog size for the current page and resizes 
     * its shell if nessessary. Also causes the container to refresh its
     * layout.
     * 
     * @param page the wizard page to use to resize the dialog
     * @since 2.0
     */
    protected void updateSize(IWizardPage page) {
        if (page == null || page.getControl() == null)
            return;
        updateSizeForPage(page);
        pageContainerLayout.layoutPage(page.getControl());
    }
    /* (non-Javadoc)
     * @see org.eclipse.jface.wizard.IWizardContainer2#updateSize()
     */
    public void updateSize() {
        updateSize(currentPage);
    }
    /**
     * Computes the correct dialog size for the given page and resizes 
     * its shell if nessessary.
     *
     * @param page the wizard page
     */
    private void updateSizeForPage(IWizardPage page) {