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
protected void fillCoolBar(ICoolBarManager coolBar) {
    	IActionBarConfigurer2 actionBarConfigurer = (IActionBarConfigurer2) getActionBarConfigurer();
        { 
            IMenuManager popUpMenu = new MenuManager();
            popUpMenu.add(new ActionContributionItem(lockToolBarAction));
            popUpMenu.add(new ActionContributionItem(editActionSetAction));
            coolBar.setContextMenuManager(popUpMenu);
        }
        coolBar.add(new GroupMarker(IIDEActionConstants.GROUP_FILE));
        { 
            IToolBarManager fileToolBar = actionBarConfigurer.createToolBarManager();
            fileToolBar.add(new Separator(IWorkbenchActionConstants.NEW_GROUP));
            fileToolBar.add(newWizardDropDownAction);
            fileToolBar.add(new GroupMarker(IWorkbenchActionConstants.NEW_EXT));
            fileToolBar.add(new GroupMarker(
                    IWorkbenchActionConstants.SAVE_GROUP));
            fileToolBar.add(saveAction);
            fileToolBar
                    .add(new GroupMarker(IWorkbenchActionConstants.SAVE_EXT));
            fileToolBar.add(printAction);
            fileToolBar
                    .add(new GroupMarker(IWorkbenchActionConstants.PRINT_EXT));
            fileToolBar
                    .add(new Separator(IWorkbenchActionConstants.BUILD_GROUP));
            fileToolBar
                    .add(new GroupMarker(IWorkbenchActionConstants.BUILD_EXT));
            fileToolBar.add(new Separator(
                    IWorkbenchActionConstants.MB_ADDITIONS));
            
            coolBar.add(actionBarConfigurer.createToolBarContributionItem(fileToolBar,