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
IWorkbenchActionConstants.TOOLBAR_FILE));
        }
        coolBar.add(new GroupMarker(IWorkbenchActionConstants.MB_ADDITIONS));
        coolBar.add(new GroupMarker(IIDEActionConstants.GROUP_NAV));
        { 
            IToolBarManager navToolBar = actionBarConfigurer.createToolBarManager();
            navToolBar.add(new Separator(
                    IWorkbenchActionConstants.HISTORY_GROUP));
            navToolBar
                    .add(new GroupMarker(IWorkbenchActionConstants.GROUP_APP));
            navToolBar.add(backwardHistoryAction);
            navToolBar.add(forwardHistoryAction);
            navToolBar.add(new Separator(IWorkbenchActionConstants.PIN_GROUP));
            navToolBar.add(pinEditorContributionItem);
            
            coolBar.add(actionBarConfigurer.createToolBarContributionItem(navToolBar,
                    IWorkbenchActionConstants.TOOLBAR_NAVIGATE));
        }
        coolBar.add(new GroupMarker(IWorkbenchActionConstants.GROUP_EDITOR));
     
        coolBar.add(new GroupMarker(IWorkbenchActionConstants.GROUP_HELP));
        
        { 
            IToolBarManager helpToolBar = actionBarConfigurer.createToolBarManager();
            helpToolBar.add(new Separator(IWorkbenchActionConstants.GROUP_HELP));
              
            helpToolBar.add(new GroupMarker(IWorkbenchActionConstants.GROUP_APP));              
            
            coolBar.add(actionBarConfigurer.createToolBarContributionItem(helpToolBar,
                    IWorkbenchActionConstants.TOOLBAR_HELP));