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
Color color= store.getBoolean(AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT)
				? null
				: createColor(store, AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND, styledText.getDisplay());
			styledText.setBackground(color);
				
			if (fBackgroundColor != null)
				fBackgroundColor.dispose();
				
			fBackgroundColor= color;
		}
	}
	/**
	 * Creates a color from the information stored in the given preference store.
	 * Returns <code>null</code> if there is no such information available.
	 */
	private Color createColor(IPreferenceStore store, String key, Display display) {
	
		RGB rgb= null;		
		
		if (store.contains(key)) {
			
			if (store.isDefault(key))
				rgb= PreferenceConverter.getDefaultColor(store, key);
			else
				rgb= PreferenceConverter.getColor(store, key);
		
			if (rgb != null)
				return new Color(display, rgb);