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
for (int i = 0; i < features.length; i++) {
			IPlatformConfiguration.IFeatureEntry feature = features[i];
			
			String pluginId = feature.getFeaturePluginIdentifier();
			if (pluginId == null) {
				continue;
			}
			String id = feature.getFeatureIdentifier();
			String version = feature.getFeatureVersion();
			String normalizedVersion = "0.0.0"; 
			if (version != null) {
				
				PluginVersionIdentifier vid = new PluginVersionIdentifier(version);
				normalizedVersion = vid.toString();
			}
			String versionedId = id + ":" + normalizedVersion; 
			ids.add(versionedId);
		}
		return ids;
	}
	
	/**
	 * Returns the ordered set of versioned feature ids new for this session.
	 * 
	 * @return ordered set of versioned feature ids (element type: <code>String</code>)
	 */
	private Set getNewlyAddedFeatures() {
		Assert.isNotNull(newlyAddedFeatures);
		return newlyAddedFeatures;
	}