Lets you move an element relative to another by specifyig a Visual to which this transform is relative.

If this proeprty is set you may use the following RelativeTo modes:

• Size: Works the same way it would without RelativeNode, but measures the size of the RelativeNode instead.
• ParentSize: Same as Size but measures the RelativeNode's parent size instead.
• PositionOffset: Moves the element to be in the same position as the element specified by RelativeNode. The offset is measured as the difference in ActualPosition between the two elements. Note that because X, Y and Vector will be interpreted as a factor, you need to specify X="1" Y="1" or Vector="1" for anything to actually happen.
• TransformOriginOffset: Works like PositionOffset, but instead measures the difference in TransformOrigin.