IWorkbenchWindow window = PlatformUI.getWorkbench()
                        .getActiveWorkbenchWindow();
                if (window instanceof WorkbenchWindow) {
                    MTrimBar topTrim = ((WorkbenchWindow) window).getTopTrim();
                for (MTrimElement element : topTrim.getChildren()) {
                    if ("PerspectiveSwitcher".equals(element.getElementId())) {                     
                        element.setVisible(false);
                        break;
                    }
                }