Bug 57454 "show intro" preference not saved until shutdown
M8 As a general rule of thumb, if a plug-in changes a preference value then it should save it immediately. (or when the user hits OK/Apply in the prefs page, etc etc) When you start M8 and close the Intro page, I noticed that the ui.ide preferences are not saved until the workbench is shutdown.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/IDEWorkbenchAdvisor.java
ProgressMonitorDialog dlg = new ProgressMonitorDialog(shell);
		final CoreException ex[] = new CoreException[1];
		try {
			dlg.run(true, true, new IRunnableWithProgress() {
				public void run(IProgressMonitor monitor) throws InvocationTargetException, InterruptedException {
					try {
						IContainer root = ResourcesPlugin.getWorkspace().getRoot();
						root.refreshLocal(IResource.DEPTH_INFINITE, monitor);
					} catch (CoreException e) {
						ex[0] = e;
					}
				}
			});
			if (ex[0] != null) {
				ErrorDialog.openError(
					shell, 
					IDEWorkbenchMessages.getString("Workspace.problemsTitle"),  
					IDEWorkbenchMessages.getString("Workspace.problemMessage"),  
					ex[0].getStatus());
			}
		} catch (InterruptedException e) {
			
		} catch (InvocationTargetException e) {
			String msg = "InvocationTargetException refreshing from local on startup"; 
			IDEWorkbenchPlugin.log(msg, new Status(IStatus.ERROR, IDEWorkbenchPlugin.IDE_WORKBENCH, 0, msg, e.getTargetException()));
		}
	}
	/**
	 * Disconnect from the core workspace.
	 */