Bug 320285 Messages inteneded for developers in the error log
The message "unsupported: isEditorAreaVisible" appears in the error log during the normal run of e4 SDK. (For instance, starting the e4 SDK on an clean workspace produces two of those messages.)
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/ModelServiceImpl.java
* org.eclipse.e4.ui.workbench.modeling.EModelService#getTrim(org.eclipse.e4.ui.model.application
	 * .ui.basic.MTrimmedWindow, org.eclipse.e4.ui.model.application.ui.SideValue)
	 */
	public MTrimBar getTrim(MTrimmedWindow window, SideValue sv) {
		List<MTrimBar> bars = window.getTrimBars();
		for (MTrimBar bar : bars) {
			if (bar.getSide() == sv)
				return bar;
		}
		
		MTrimBar newBar = BasicFactoryImpl.eINSTANCE.createTrimBar();
		newBar.setSide(sv);
		window.getTrimBars().add(newBar);
		return newBar;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.modeling.EModelService#getTopLevelWindowFor(org.eclipse.e4.ui
	 * .model .application.ui.MUIElement)
	 */
	public MWindow getTopLevelWindowFor(MUIElement element) {
		EObject eObj = (EObject) element;
		while (eObj != null && !(eObj.eContainer() instanceof MApplication))
			eObj = (EObject) eObj.eContainer();
		if (eObj instanceof MWindow)
			return (MWindow) eObj;
		return null; 
	}