Anti-Aliasing causes some edges to be visible when they should not be
I have attached a demo file.
The demo has three stacked rectangles (mouse-out, mouse-over and mouse-clicked) on a high-contrast background. A hotspot over the rectangles is used to trigger mouse-over and mouse-click events to determine which rectangle becomes visible.
When the hotspot is clicked, the uppermost rectangle becomes visible, but the edges of the rectangle beneath it are still visible. This is especially noticeable if you move your mouse in and out of the hotspot after clicking - you'll see dark edges appear and disappear. I believe it is anti-aliasing that is causing this. I'm not a graphics expert so could be wrong.
I have repeated the test using JPG images rather than native Storyline shapes and get the same issue.
Is this behavior considered a bug?
Many thanks in advance.