Creates a Popup for the Component owner containing the Component contents. owner is used to determine which Window the new Popup will parent the Component the Popup creates to. A null owner implies there is no valid parent. x and y specify the preferred initial location to place the Popup at. Based on screen size, or other paramaters, the Popup may not display at x and y.

Parameters:

owner		Component mouse coordinates are relative to, may be null
contents		Contents of the Popup
x		Initial x screen coordinate
y		Initial y screen coordinate

Returns:  Popup containing Contents

Exceptions:

IllegalArgumentException

if contents is null