Open XML Editor in Ink.
Click on the node in the tree that puts a highlight box around the object.
Go to the top of the XML Editor and run the pointer over the faded boxes - they don't look active but they are - and Indent. Unindent, up arrow or down arrow until it's in the Copper group you want.
If you unindent or indent and the part disappears zoom out until you see it and drag it back in position, or reverse one step and note the node position in the main screen on the top bar - must be in arrow select - and just type in the coordinates again.
Are you sure you want that rectangle in copper because that will become a copper pad or a hole if it has a hole.