From be35e916be1f800cd380112b07b5be3859c9a793 Mon Sep 17 00:00:00 2001
From: Thomas Lopez <thomas.lopez@unity3d.com>
Date: Fri, 10 Jul 2026 16:16:57 -0400
Subject: [PATCH 1/2] fixing autolightmap uv not rebuilding the uvs properly
 after certain operations in the uv editor

---
 Editor/EditorCore/AutoUVEditor.cs | 18 ------------------
 Editor/EditorCore/UVEditor.cs     |  3 +++
 2 files changed, 3 insertions(+), 18 deletions(-)

diff --git a/Editor/EditorCore/AutoUVEditor.cs b/Editor/EditorCore/AutoUVEditor.cs
index 0ae9497e7..5c9a9b9ff 100644
--- a/Editor/EditorCore/AutoUVEditor.cs
+++ b/Editor/EditorCore/AutoUVEditor.cs
@@ -214,26 +214,12 @@ public static bool OnGUI(ProBuilderMesh[] selection, float width)
             {
                 for (int i = 0; i < selection.Length; i++)
                     TextureGroupSelectedFaces(selection[i]);
-
-                ProBuilderEditor.Refresh();
             }
 
             if (GUILayout.Button(gc_BreakSelected))
             {
                 SetTextureGroup(selection, -1);
-
-                foreach (var kvp in MeshSelection.selectedFacesInEditZone)
-                {
-                    kvp.Key.ToMesh();
-                    kvp.Key.Refresh();
-                    kvp.Key.Optimize();
-                }
-
-                SceneView.RepaintAll();
-
                 s_AutoUVSettingsDiff["textureGroup"] = false;
-
-                ProBuilderEditor.Refresh();
             }
 
             /* Select all in current texture group */
@@ -241,8 +227,6 @@ public static bool OnGUI(ProBuilderMesh[] selection, float width)
             {
                 for (int i = 0; i < selection.Length; i++)
                     selection[i].SetSelectedFaces(System.Array.FindAll(selection[i].facesInternal, x => x.textureGroup == textureGroup));
-
-                ProBuilderEditor.Refresh();
             }
 
             if (GUILayout.Button(gc_Reset))
@@ -260,8 +244,6 @@ public static bool OnGUI(ProBuilderMesh[] selection, float width)
 
                     UVEditing.SplitUVs(selection[i], selection[i].GetSelectedFaces());
                 }
-
-                ProBuilderEditor.Refresh();
             }
 
             GUI.backgroundColor = PreferenceKeys.proBuilderLightGray;
diff --git a/Editor/EditorCore/UVEditor.cs b/Editor/EditorCore/UVEditor.cs
index 69ea72e06..1b599bfc3 100644
--- a/Editor/EditorCore/UVEditor.cs
+++ b/Editor/EditorCore/UVEditor.cs
@@ -2617,7 +2617,10 @@ void DrawAutoModeUI()
                     {
                         pb.ToMesh();
                         pb.Refresh();
+                        pb.Optimize();
                     }
+                    ProBuilderEditor.Refresh();
+                    SceneView.RepaintAll();
                 }
 
                 foreach (var kvp in MeshSelection.selectedFacesInEditZone)

From 155a38bc6994a063630701bae7dc66de67ca2227 Mon Sep 17 00:00:00 2001
From: Thomas Lopez <thomas.lopez@unity3d.com>
Date: Fri, 10 Jul 2026 16:19:46 -0400
Subject: [PATCH 2/2] changelog

---
 CHANGELOG.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 622b852d8..72bb708fa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Fixed
+
+- [UUM-133528] Fixed an issue where using some UV Editor actions would clear a mesh's Lightmap UVs without regenerating them.
+
 ## [6.1.2] - 2026-06-11
 
 ### Fixed