Update manager doesnt minimize on clicking the icon on bottom panel

Once you open the update manager, if you want to minimize it (or maximise it if minimised) by clicking on the rectangular button on the bottom panel (i dont know by what name is that 'button' called, the rectangular thing which appear on the bottom panel on opening a window/application), it does not minimize!
Works fine with any other window/explorer, but not with update manager. I use LM12, default Gnome3.