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
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IPageListener;
import org.eclipse.ui.IWorkbenchActionConstants;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.actions.ActionFactory;
import org.eclipse.ui.actions.BuildAction;
import org.eclipse.ui.actions.ContributionItemFactory;
import org.eclipse.ui.actions.NewWizardMenu;
import org.eclipse.ui.actions.ActionFactory.IWorkbenchAction;
import org.eclipse.ui.application.ActionBarAdvisor;
import org.eclipse.ui.application.IActionBarConfigurer;
import org.eclipse.ui.ide.IDEActionFactory;
import org.eclipse.ui.ide.IIDEActionConstants;
import org.eclipse.ui.internal.IPreferenceConstants;
import org.eclipse.ui.internal.WorkbenchPlugin;
import org.eclipse.ui.internal.ide.actions.BuildSetMenu;
import org.eclipse.ui.internal.ide.actions.BuildUtilities;
import org.eclipse.ui.internal.ide.actions.QuickMenuAction;
import org.eclipse.ui.internal.ide.actions.RetargetActionWithDefault;
import org.eclipse.ui.internal.provisional.application.IActionBarConfigurer2;
import org.eclipse.ui.internal.util.StatusLineContributionItem;
/**
 * Adds actions to a workbench window.
 */
public final class WorkbenchActionBuilder extends ActionBarAdvisor {
    private final IWorkbenchWindow window;