Bug 157985 [Workbench] Add 'Hide toolbar' action to context menu
M2 The 'Hide toolbar' action should be added to the context menu on toolbars. That's where I first looked for it.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/WorkbenchActionBuilder.java
private NewWizardMenu newWizardMenu;
    private IContributionItem pinEditorContributionItem;
    
    
    private StatusLineContributionItem statusLineItem;
    private Preferences.IPropertyChangeListener prefListener;
    
    
    private IPropertyChangeListener propPrefListener;
    private IPageListener pageListener;
    private IResourceChangeListener resourceListener;
    
    /**
     * Indicates if the action builder has been disposed
     */
    private boolean isDisposed = false;
    
    /**
     * Constructs a new action builder which contributes actions
     * to the given window.
     * 
     * @param configurer the action bar configurer for the window
     */
    public WorkbenchActionBuilder(IActionBarConfigurer configurer) {
        super(configurer);
        window = configurer.getWindowConfigurer().getWindow();
    }
    /**
     * Returns the window to which this action builder is contributing.