public void setCenterWindow(boolean center) {
        putBoolean("CenterWindow", center);
    }
Enables or disables the Center Window flag.

<p>The Center Window flag is used only with LWJGL3 and has no effect on
fullscreen windows. It defaults to true.

@param center true to center the window on the desktop, false to position
    the window at (WindowXPosition, WindowYPosition)
jme3-core/src/main/java/com/jme3/system/AppSettings.java