Bug 299272 Renderer cannot handle an MPart with a null label
java.lang.IllegalArgumentException: Argument cannot be null at org.eclipse.swt.SWT.error(SWT.java:4049) at org.eclipse.swt.SWT.error(SWT.java:3983) at org.eclipse.swt.SWT.error(SWT.java:3954) at org.eclipse.e4.ui.widgets.CTabItem.setText(CTabItem.java:1013) at org.eclipse.e4.workbench.ui.renderers.swt.StackRenderer.showChild(StackRenderer.java:296) at org.eclipse.e4.workbench.ui.renderers.swt.LazyStackRenderer.processContents(LazyStackRenderer.java:92) at org.eclipse.e4.ui.workbench.swt.internal.PartRenderingEngine.createGui(PartRenderingEngine.java:300) at org.eclipse.e4.ui.workbench.swt.internal.PartRenderingEngine.createGui(PartRenderingEngine.java:349) at org.eclipse.e4.workbench.ui.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:54) at org.eclipse.e4.ui.workbench.swt.internal.PartRenderingEngine.createGui(PartRenderingEngine.java:300) at org.eclipse.e4.ui.workbench.swt.internal.PartRenderingEngine.createGui(PartRenderingEngine.java:349) at org.eclipse.e4.workbench.ui.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:54) at org.eclipse.e4.workbench.ui.renderers.swt.WBWRenderer.processContents(WBWRenderer.java:369) at org.eclipse.e4.ui.workbench.swt.internal.PartRenderingEngine.createGui(PartRenderingEngine.java:300) at org.eclipse.e4.ui.workbench.swt.internal.PartRenderingEngine.createGui(PartRenderingEngine.java:349) at org.eclipse.e4.ui.workbench.swt.internal.PartRenderingEngine$4.run(PartRenderingEngine.java:510)
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/workbench/ui/renderers/swt/StackRenderer.java
activate(part);
			}
		});
	}
	private void showTab(MElementContainer<MUIElement> parentElement,
			MUIElement element) {
		CTabFolder ctf = (CTabFolder) getParentWidget(element);
		Control ctrl = (Control) element.getWidget();
		CTabItem cti = findItemForPart(parentElement, element);
		cti.setControl(ctrl);
		ToolBar tb = getToolbar(element);
		if (tb != null) {
			Control curTR = ctf.getTopRight();
			if (curTR != null)
				curTR.dispose();
			if (tb.getSize().y > ctf.getTabHeight())
				ctf.setTabHeight(tb.getSize().y);
			
			
			String cssClassName = (String) ctf
					.getData("org.eclipse.e4.ui.css.CssClassName"); 
			stylingEngine.setClassname(tb, cssClassName);
			ctf.setTopRight(tb, SWT.RIGHT);
			ctf.layout(true);