Change the layering order of objects
With any two objects on the artboard in Microsoft Expression Blend, one object will appear in front of the other. The bottom of the list of objects in the Objects and Timeline panel is the front-most object. When you insert an object into a document or layout panel, the object is automatically placed in front of other objects in the active container object. To change the order of objects, you can use the Order commands on the Object menu or drag the objects in the objects view in the Objects and Timeline panel.
Do one of the following:
In the Objects and Timeline panel, drag the objects up or down to create the desired layering order.
Select the objects that you want to move, point to Order on the Object menu, and then click one of the following:
Bring to Front to bring the object all the way to the front of the stack.
Bring Forward to bring the object forward one step in the stack.
Send Backward to send the object back one step in the stack.
Send to Back to send the object all the way to the back of the stack.
You can also change the order of objects by using the Order commands when you right-click an object on the artboard or in the Objects and Timeline panel.