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
MToolControl trimCtrl = (MToolControl) find(trimId, window1);
			if (trimCtrl != null) {
				IEclipseContext ctxt = EclipseContextFactory.create();
				ctxt.set("show", true); 
				ContextInjectionFactory.invoke(trimCtrl.getObject(), Execute.class, ctxt);
			}
		}
		MUIElement parent = element.getParent();
		if (parent == null) {
			MPlaceholder ph = findPlaceholderFor(window, element);
			if (ph != null) {
				element = ph;
				parent = element.getParent();
			}
		}
		if (parent != null) {
			
			if (!element.isToBeRendered())
				element.setToBeRendered(true);
			((MElementContainer<MUIElement>) parent).setSelectedElement(element);
			bringToTop(window, parent);
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.modeling.EModelService#findPlaceholderFor(org.eclipse.e4.ui.model
	 * .application.ui.basic.MWindow, org.eclipse.e4.ui.model.application.ui.MUIElement)
	 */