When objects are planar or have scale of 0 in Z gumball axis, the scaling axis is not shown.
This is practical because you can easily tell when geometry is planar in certain axis.
The thing is that sometimes even after scaling in Z axis to 0, the handle keeps displaying… so you are never sure if it’s actually 0, and you start doubting if you have already scaled it…
For instance in SubD geometry, it never goes away…
Here you can see the faces are clearly planar to cplane. Despite this it still shows a Z handle. It happens 100% when using custom planes that are not world, and aligning Gumball to Cplane. It mostly happens when selecting edge loops or rings, or multiple coplanar faces. Works fine with individual.
Even after scaling to 0, the handle will disappear momentarily but come back after a new selection.
It also happens with polysurfaces.
These are my settings
