any sprite that starts off turned off, or alpha is 0 positioned when a scene is created, and is within a clipped or constrained panel, will not appear when alpha is set to a visible value, or it is enabled.
Real world example.
Add 2 toggle buttons to a scene, making them the child of a clipped panel, with one selected on start, add them to the same group.
play scene , click on the unselected button, button press is acknowledged(button changes colour), other button deselects, but clicked on button never shows the selected state on mouse up.
