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
/**
	 * Determine if the element passes the matching test for all non-null parameters.
	 * 
	 * @param element
	 *            The element to test
	 * @param id
	 *            The Id
	 * @param clazz
	 *            The class that element must be an instance of
	 * @param tagsToMatch
	 *            The tags to check, <b>all</b> the specified rags must be in the element's tags
	 * @return <code>true</code> iff all the tests pass
	 */
	private boolean match(MUIElement element, String id, Class clazz, List<String> tagsToMatch) {
		if (id != null && !id.equals(element.getElementId()))
			return false;