Determine the owner of the given selection.
Note that the return value may be owned by a different process if a foreign window was previously created for that window, but a new foreign window will never be created by this call.
| display |
a Display |
| selection |
an atom indentifying a selection |
|
if there is a selection owner for this window, and it is a window known to the current process, the Window that owns the selection, otherwise null. |