Missing "name" in tree with PROTO file

[ShuffleWire]

Describe the Bug
When I use the following PROTO, no name is displayed in the tree.

world file

#VRML_SIM R2021b utf8
# Named Transform
PROTO NamedTransform [

field SFVec3f    translation       0 0 0

field SFRotation rotation          0 1 0 0

unconnectedField SFString   name              "name"

field MFNode     children	     []

]

{

Transform {

translation IS translation

rotation IS rotation

children IS children

}

}

Expected behavior
In the tree, when the node is folded, I would like to read
NamedTransform "name".
If instead of Transform my base Node is, for instance, a solid, (and change unconnectedField to field, and add name IS name), I get it right.

Additional context
This PR was related to that, but I not sure if it's a code issue, a miss usage of PROTO, or just not possible.
#3198

Ultimately, the goal was to "add" field to an existing node. Maybe their is another way more compliant with Webots.