Lock a GameObject's transform so it cannot be changed in the Scene editor?

I have a UI I’m working on, and I’m using an asset from the store. The way the prefabs are set up, there is a lot of nesting (and for the most part I cannot consolidate them into a more simple structure).

I’m running into an annoying issue. I’m moving and resizing UI elements while I’m designing the UI layout, and doing so visually in the Scene editor, by dragging elements around, resizing by grabbing corners, etc.

The way the gameobjects are nested, sometimes when I click to select then grab and resize a border, I’m resizing a child object instead of the parent. The major PITA issue is this actually works visually - everything looks fine. Until I later grab the parent object for another reason and go to move it, and notice the borders are all wonky. Some scripts are based on the size and location of the parent, and the child objects have moved around or resized to be different than the bounds of the parent, which breaks stuff.

Using the “finger” icon in the Hierarchy window to make the problematic gameobjects not selectable works great. Until I duplicate the main object to add another panel - all the “can’t select me” flags get turned off. Editing the prefab doesn’t help - setting “cant select me” in there doesn’t carry over when added to the scene. Can’t do it with code because while I could make all the child windows fix themselves once I hit play - that doesn’t help the issue while I’m designing the UI.

The way the asset was made, some of these parent/child objects are necessary, due to vertical layout groups, etc.

I’ve seen the rect transform box grayed out before, or portions of it unaccessable (due to being driven by the canvas, etc). How the heck can I make it so that specific objects are permanently not selectable in the scene editor, or lock a child objects transform to it’s parents?

I think this is via a custom editor for RectTransform but I’m not sure. Most of the UnityEngine.UI is open source so maybe you can see what they did?

https://github.com/Unity-Technologies/uGUI

Perhaps you can even extend their custom editor and put a serializable checkbox that locks the Transform, or somesuch construct.