Unity UI Rect Transform, Anchor presets not working

Hello all,

I'm using Unity 2020.1.10.f1 Personal.

I have a Canvas object, below that a child object for a healthbar UI, and below that a slider object.
No matter what object if its the canvas of its children, when I try to click the Anchor presets within the Rect Transform in the inspector, nothing happens, it doesn't pop up the options for presets, so I have to manullay move things around.

Is this a bug or am I doing something wrong here?

Thanks