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
placeholder.setVisible(vis);
		placeholder.setToBeRendered(tbr);
		
		elementParent.getChildren().add(elementIndex, placeholder);
		phParent.getChildren().add(phIndex, element);
	}
	private void combine(MPartSashContainerElement toInsert, MPartSashContainerElement relTo,
			MPartSashContainer newSash, boolean newFirst, int ratio) {
		MElementContainer<MUIElement> curParent = relTo.getParent();
		int index = curParent.getChildren().indexOf(relTo);
		curParent.getChildren().remove(relTo);
		if (newFirst) {
			newSash.getChildren().add(toInsert);
			newSash.getChildren().add(relTo);
		} else {
			newSash.getChildren().add(relTo);
			newSash.getChildren().add(toInsert);
		}
		
		toInsert.setContainerData(Integer.toString(ratio));
		relTo.setContainerData(Integer.toString(100 - ratio));
		
		curParent.getChildren().add(index, newSash);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.modeling.EModelService#insert(org.eclipse.e4.ui.model.application
	 * .MPartSashContainerElement, org.eclipse.e4.ui.model.application.MPartSashContainerElement,