If you use a Transform widget to perform a 3D transformation, it breaks the UI (you cannot click on a button anymore). Scaling and rotateZ seem to be fine, but rotateX or rotateY seem to break things if you rotate more than a few degrees.

To reproduce, run the file https://gist.github.com/wmleler/cfc18137ce7db77d7e599e179dee4619 (change its name to main.dart, of course)

To rotate things, just touch the screen and pan around, like this (the little moving circle is the position of the user's finger):

As long as the screen is not rotated very much, you can still tap the FAB and increment the counter. Rotate a little more and the tap target is slightly away from the FAB itself and you can still find it by tapping around. But rotate more than that, and you can't even find the tap target.