Bug 16923 Auto activation preference dialog
The auto activation characters and Timeout Text fields are enabled even when Auto activation itself is disabled. This was confusing to me because I thought that "." should cause automatic code assist, but it wasn't. Disabling the feature should disable the controls what modify the details for that feature.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/JavaEditorPreferencePage.java
fOverlayStore.propagate();
		JavaPlugin.getDefault().savePluginPreferences();
		return true;
	}
	
	/*
	 * @see PreferencePage#performDefaults()
	 */
	protected void performDefaults() {
		
		fFontEditor.loadDefault();
		
		fOverlayStore.loadDefaults();
		initializeFields();
		handleSyntaxColorListSelection();
		handleAppearanceColorListSelection();
		super.performDefaults();
		
		fPreviewViewer.invalidateTextPresentation();
	}
	
	/*
	 * @see DialogPage#dispose()
	 */
	public void dispose() {
		
		if (fJavaTextTools != null) {
			fJavaTextTools= null;
		}