Button over portal does not work on iPad
On an iPad layout based upon the cool grey touch design I have a portal. I have placed a transparent button over this portal which switches layout when tapped. This works as expected on the desktop, however, on the iPad this button appears always under the portal and not above. This becomes apparent when filling the button with a solid color. Hence tapping the portal on the iPad only selects portal rows and does not execute the buttons action. Is this a known bug or am I missing something?