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
progressMonitorPart
                .setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
        progressMonitorPart.setVisible(false);
        
        Label separator = new Label(composite, SWT.HORIZONTAL | SWT.SEPARATOR);
        separator.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
        applyDialogFont(progressMonitorPart);
        return composite;
    }
    /**
     * Create the progress monitor part in the receiver.
     * @param composite
     * @param pmlayout
     * @return ProgressMonitorPart
     */
    protected ProgressMonitorPart createProgressMonitorPart(
            Composite composite, GridLayout pmlayout) {
        return new ProgressMonitorPart(composite, pmlayout, SWT.DEFAULT) {
            String currentTask = null;
            /* (non-Javadoc)
             * @see org.eclipse.jface.wizard.ProgressMonitorPart#setBlocked(org.eclipse.core.runtime.IStatus)
             */
            public void setBlocked(IStatus reason) {
                super.setBlocked(reason);
                if (!lockedUI)
                    getBlockedHandler().showBlocked(getShell(), this, reason,
                            currentTask);
            }
            /* (non-Javadoc)
             * @see org.eclipse.jface.wizard.ProgressMonitorPart#clearBlocked()