Godot version:
3.2.1
OS/device including version:
macOS 10.15.5
Issue description:
When the tiles are symmetry, it's impossible to tell the status of the Flip Horizontally and Flip Vertically Buttons.
These buttons should have different icons for on and off.
Steps to reproduce:
Minimal reproduction project:

They are not status, they are actions. Those buttons were status before and thus had status indication, but they were removed as they were confusing. Considering the a 180 degree rotation is equivalent to both an horizontal and a vertical mirror, it made things confusing when two rotations would cause the symmetry indicators to turn on when you rotated the tile.
You can know if a sprite is not in it's default transform if the "clean" action on the right is available. So on your example, there is no symmetry active.
Most helpful comment
They are not status, they are actions. Those buttons were status before and thus had status indication, but they were removed as they were confusing. Considering the a 180 degree rotation is equivalent to both an horizontal and a vertical mirror, it made things confusing when two rotations would cause the symmetry indicators to turn on when you rotated the tile.
You can know if a sprite is not in it's default transform if the "clean" action on the right is available. So on your example, there is no symmetry active.