Change pixelmap in icon widget

Hello.

 

With GUIX Studio, I inserted an icon (Insert - Button - Icon). In this icon I have configured an image in "Normal Pixelmap" and another in "Selected Pixelmap" so that depending on whether the icon is selected, one image or another is displayed. The problem is that I can not find how to select or deselect the icon in runtime so that it changes the image.

 

The idea is that, depending on the state of a signal, one image or another is displayed.

Can someone help me?

Thank you.