Bug 143659 [Accessibility] Press Tab key will cause eclipse crash when focus isn't on any report item in Editor view
Press Tab key will cause eclipse crash when focus isn't on any report item in Editor view Steps to reproduce: 1. New a report 2. Click the blank area in Layout of Editor view 3. Press Tab key Expected result: Something in layout will get focus Actual result: Eclipse crashed
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/editors/parts/ReportFocusTraverseManager.java
* apply focus to root figure's first focusable child
		 */
		if (focusOwner == null) {
			if (root.getChildren().size() != 0) {
				nextFocusOwner = ((IFigure)root.getChildren().get(0));
				if (isFocusEligible(nextFocusOwner))
					return nextFocusOwner;
			} else
				return null;
		}
		while (!found) {
			IFigure parent = nextFocusOwner.getParent();
			
			/*
			 * Figure traversal is implemented using the pre-order left to right
			 * tree traversal algorithm.
			 *  
			 * If the focused sibling has children, traverse to its leftmost child.
			 * If the focused sibling has no children, traverse to the sibling
			 * to its right.
			 * If there is no sibling to the right, go up the tree until a node
			 * with untraversed siblings is found.
			 */
			List siblings = parent.getChildren();
			int siblingPos = siblings.indexOf(nextFocusOwner);		
			if (nextFocusOwner.getChildren().size() != 0) {
				nextFocusOwner = ((IFigure)(nextFocusOwner.getChildren().get(0)));		
				if (isFocusEligible(nextFocusOwner))				
					found = true;	
			} else if (siblingPos < siblings.size() - 1) {