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
for (MTrimBar bar : bars) {
				findElementsRecursive(bar, id, type, tagsToMatch, elements);
			}
		}
		
		if (searchRoot instanceof MWindow) {
			MWindow window = (MWindow) searchRoot;
			for (MWindow dw : window.getWindows()) {
				findElementsRecursive(dw, id, type, tagsToMatch, elements);
			}
		}
		if (searchRoot instanceof MPerspective) {
			MPerspective persp = (MPerspective) searchRoot;
			for (MWindow dw : persp.getWindows()) {
				findElementsRecursive(dw, id, type, tagsToMatch, elements);
			}
		}
		
		if (searchRoot instanceof MPlaceholder) {
			MPlaceholder ph = (MPlaceholder) searchRoot;
			findElementsRecursive(ph.getRef(), id, type, tagsToMatch, elements);
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.modeling.EModelService#getAllElements(org.eclipse.e4.ui.model.
	 * application.MUIElement, java.lang.String, java.lang.Class, java.util.List)
	 */