Trying 'uistack' did not solve my problem. This is because the ActiveX control cannot be manipulated with 'uistack'. Only 'uicontrol' elements can.
However, I was able to place a button on top of the ActiveX control that serves the purpose of marking my laser spot by creating the button after the ActiveX control in the 'OpeningFcn'. Due to the draw order of components that have the same parent, the ActiveX control is drawn first, then the button on top. The key is making the GUI the parent of both the ActiveX control and button.
Thanks, Kevin