As a newcomer, I find this issue quite significant for workflow efficiency. Having to repeatedly click "Edit Collider" for every minor adjustment in Prefab mode can disrupt the editing process and slow down development, especially when working on complex shapes. It would be great if the "Edit Collider" option could remain active until manually deselected, allowing for multiple edits in one session. This change would make the feature more intuitive and user-friendly. It's good to see such feedback being raised, as improvements in usability have a huge impact on productivity. Looking forward to seeing this resolved in future updates!

This seems not to be fixed.
At least not for me.
Using Unity 2019.2.0f.
rolaif.com

Just started happening to me. I edited my collider with no issue when I created it, but now I can't edit it without having to open the editor again every single time I move a point.

Seems to still be present in 2019.2.4f1

This seems not to be fixed.
At least not for me.
Using Unity 2019.2.0f.

If you turn off "Auto Save" this doesnt happen.

Is there any way to edit comments? xD
My solution below requires LinQ, null propagation

Here's an edited version that works with polygoncollider2d. It seems that PolygonCollider2DEditor has to be set to edit mode in the next "frame" rather than when its exit mode ended.

[InitializeOnLoadMethod]
public static void InitLoad()
{
EditMode.onEditModeEndDelegate -= Collider2DEditModeFixer;
EditMode.onEditModeEndDelegate += Collider2DEditModeFixer;
}

static void Collider2DEditModeFixer(Editor editor)
{
if (EditMode.editMode == EditMode.SceneViewEditMode.Collider || EditMode.IsOwner(editor)) return;

var sel = Selection.activeGameObject;
var cols = sel?.GetComponents<Collider2D>();
if (cols == null || cols.Length == 0) return;

var t = editor.target as Collider2D;
if (t != null && (cols?.Contains(t) ?? false))
{
EditorApplication.delayCall += () => EditMode.ChangeEditMode(EditMode.SceneViewEditMode.Collider, t.bounds, editor);
}
}

I created an automated fix for this. Sometimes i have multiple colliders in the same object so choosing just the first editor to edit won't work.
The only downside is that if you want to exit the collider edit mode you have to select another object.

[InitializeOnLoadMethod]
public static void InitLoad()
{
EditMode.onEditModeEndDelegate -= Collider2DEditModeFixer;
EditMode.onEditModeEndDelegate += Collider2DEditModeFixer;
}

static void Collider2DEditModeFixer(Editor editor)
{
var sel = Selection.activeGameObject;
var cols = sel?.GetComponents<Collider2D>();

var t = editor.target as Collider2D;
if (t != null && cols.Contains(t))
{
EditMode.ChangeEditMode(EditMode.SceneViewEditMode.Collider, t.bounds, editor);
}
}

I guess you do know the workaround, but anyways: editing an GameObject's collider in the scene, will not quit "Edit Collider" mode.

Also, I composed a plugin/Script for working in Prefab Editor, (works by hitting Shift+E on every change... xD .. better than nothing!), with some code I found in stack-overflow :

----------------------------------
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;

public class MenuItems
{
[MenuItem("BugFixes/Edit Collider Mode #_e")] // This is Shift + e
private static void EditCollider()
{
var sel = Selection.activeGameObject; if(!sel) return;
var col = sel.GetComponent<Collider2D>(); if (!col) return;

if (UnityEditorInternal.EditMode.editMode == UnityEditorInternal.EditMode.SceneViewEditMode.Collider)
UnityEditorInternal.EditMode.ChangeEditMode(UnityEditorInternal.EditMode.SceneViewEditMode.None, new Bounds(), null);
else
{
System.Type colliderEditorBase = System.Type.GetType("UnityEditor.ColliderEditorBase,UnityEditor.dll");
Editor[] colliderEditors = Resources.FindObjectsOfTypeAll(colliderEditorBase) as Editor[];

if (colliderEditors == null || colliderEditors.Length <= 0) return;

UnityEditorInternal.EditMode.ChangeEditMode(UnityEditorInternal.EditMode.SceneViewEditMode.Collider, col.bounds, colliderEditors[0]);
}
Debug.Log("EditMode: " + UnityEditorInternal.EditMode.editMode);
}
}
----------------------------------

The link from which I found most of the code (ready) is this one:
https://forum.unity.com/threads/creating-a-hotkey-to-get-into-edit-collider-mode.474706/
So, most credits go to him.

P.S.: "Place in a folder called 'Editor' in order to work as a plugin", that's what I did, and it worked.