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
* MUIElement, org.eclipse.e4.ui.model.application.MElementContainer, boolean)
	 */
	public void move(MUIElement element, MElementContainer<MUIElement> newParent,
			boolean leavePlaceholder) {
		move(element, newParent, -1, leavePlaceholder);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.modeling.EModelService#move(org.eclipse.e4.ui.model.application.
	 * MUIElement, org.eclipse.e4.ui.model.application.MElementContainer, int)
	 */
	public void move(MUIElement element, MElementContainer<MUIElement> newParent, int index) {
		move(element, newParent, index, false);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.modeling.EModelService#move(org.eclipse.e4.ui.model.application.
	 * MUIElement, org.eclipse.e4.ui.model.application.MElementContainer, int, boolean)
	 */
	public void move(MUIElement element, MElementContainer<MUIElement> newParent, int index,
			boolean leavePlaceholder) {
		
		MElementContainer<MUIElement> curParent = element.getParent();
		int curIndex = curParent.getChildren().indexOf(element);
		
		newParent.getChildren().add(index, element);