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.addons.swt/src/org/eclipse/e4/ui/workbench/addons/perspectiveswitcher/PerspectiveSwitcher.java
psTB.addDisposeListener(new DisposeListener() {
			public void widgetDisposed(DisposeEvent e) {
				disposeTBImages();
			}
		});
		final ToolItem createItem = new ToolItem(psTB, SWT.PUSH);
		createItem.setImage(getOpenPerspectiveImage(psTB.getDisplay()));
		createItem.setToolTipText("Open Perspective"); 
		createItem.addSelectionListener(new SelectionListener() {
			public void widgetSelected(SelectionEvent e) {
				selectPerspective();
			}
			public void widgetDefaultSelected(SelectionEvent e) {
				selectPerspective();
			}
		});
		new ToolItem(psTB, SWT.SEPARATOR);
		MPerspectiveStack stack = getPerspectiveStack();
		if (stack != null) {
			
			for (MPerspective persp : stack.getChildren()) {
				if (persp.isToBeRendered()) {
					addPerspectiveItem(persp);
				}
			}
		}
	}
	private Image getOpenPerspectiveImage(Display display) {
		ImageDescriptor desc = WorkbenchImages
				.getImageDescriptor(IWorkbenchGraphicConstants.IMG_ETOOL_NEW_PAGE);