Cannot change icon in button

I have selected “yes” in the Button > Appearance > Icon dropdown for my button because I want a round shaded button with an icon in it. However, I am not able to change the icon from the standard star- not able to click on the icon itself nor is there a thumb to click on the left panel as there usually is when using an icon. Another workaround was to simply add an icon, but then I was unable to get the round shaded “button” look behind it (only options were a colored circle around it). I know there is a way to accomplish this because it exists on another blocs site I have worked on, BUT I can’t duplicate the button/icon between the two site files. Working in blocs 1.6.2. Help please!