Steps to reproduce:

1. Create a new linear colorspace project
2. Create a UIDocument with a dark background (rgb(22,22,22))
3. Apply on UIDocument GameObject

Actual results: The UIDoc looks much brighter

Expected results: The UIDoc with opaque background should have the same appearance

Reproducible with versions: 

Not reproducible with versions: 

Can’t test with versions: 

Tested on (OS): 

Notes:

• This seems to be a side-effect of the IMGUI code running before the Scene/Game view. Callstack:

     Void UnityEngine.UIElements.UIR.CommandList:Execute ()+0xd at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\Renderer\UIRCommandList.cs:[85:13-85:53]    C#
     Void UnityEngine.UIElements.UIRenderer:OnRenderNodeExecute (UIRenderer, Int32, Int32)+0x42 at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\Native\Renderer\UIRenderer.bindings.cs:[34:17-34:50]    C#
     Void UnityEditor.Handles:Internal_DrawCameraWithGrid (Camera, DrawCameraMode, DrawGridParameters, Boolean, Boolean)+0x29 at :-1    C#
     Void UnityEditor.Handles:DrawCameraImpl (Rect, Camera, DrawCameraMode, Boolean, DrawGridParameters, Boolean, Boolean, Boolean, GameObject[])+0xcd at E:\UnitySrc\unity-trunk\Editor\Mono\Handles\Handles.cs:[1649:25-1649:117]    C#
     Void UnityEditor.Handles:DrawCameraStep1 (Rect, Camera, DrawCameraMode, DrawGridParameters, Boolean, Boolean)+0xc at E:\UnitySrc\unity-trunk\Editor\Mono\Handles\Handles.cs:[1672:13-1672:107]    C#
     Void UnityEditor.SceneView:DoDrawCamera (Rect, Rect, Boolean)+0x1d8 at E:\UnitySrc\unity-trunk\Editor\Mono\SceneView\SceneView.cs:[2336:17-2336:125]    C#
     Void UnityEditor.SceneView:DoOnGUI ()+0x28a at E:\UnitySrc\unity-trunk\Editor\Mono\SceneView\SceneView.cs:[2670:13-2670:105]    C#
     Void UnityEditor.SceneView:OnSceneGUI ()+0x1 at E:\UnitySrc\unity-trunk\Editor\Mono\SceneView\SceneView.cs:[2578:48-2578:57]    C#
     Void UnityEngine.UIElements.IMGUIContainer:DoOnGUI (Event, Matrix4x4, Rect, Boolean, Rect, Action, Boolean)+0x261 at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\IMGUIContainer.cs:[377:25-377:40]    C#
     Boolean UnityEngine.UIElements.IMGUIContainer:HandleIMGUIEvent (Event, Matrix4x4, Rect, Action, Boolean)+0xd0 at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\IMGUIContainer.cs:[702:13-702:99]    C#
     Void UnityEngine.UIElements.IMGUIContainer:DoIMGUIRepaint ()+0x87 at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\IMGUIContainer.cs:[564:21-564:138]    C#
>    Void UnityEngine.UIElements.UIR.RenderChainCommand:ExecuteNonDrawMesh (DrawParams, Single, Exception)+0xf2 at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\Renderer\UIRenderer\UIRenderers.cs:[142:25-142:36]    C#
     Void UnityEngine.UIElements.UIR.UIRenderDevice:EvaluateChain (RenderChainCommand, Material, Texture, Texture, Nullable`1, Single, Boolean, TextureSlotCount, Boolean, Exception)+0x62d at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\Renderer\UIRenderer\UIRenderDevice.cs:[1108:25-1108:101]    C#
     Void UnityEngine.UIElements.UIR.RenderTreeManager:RenderSingleTree (RenderTree, RenderTexture, RectInt, Rect)+0x178 at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\Renderer\UIRRenderTreeManager.cs:[413:13-423:41]    C#
     Void UnityEngine.UIElements.UIR.RenderTreeManager:RenderRootTree ()+0x72 at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\Renderer\UIRRenderTreeManager.cs:[358:13-358:79]    C#
     Void UnityEngine.UIElements.UIRRepaintUpdater:Render ()+0x2a at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\Renderer\UIRRepaintUpdater.cs:[145:13-145:48]    C#
     Void UnityEngine.UIElements.BaseVisualElementPanel:Render ()+0x6 at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\Panel.cs:[911:41-911:63]    C#
     Void UnityEngine.UIElements.Panel:Render ()+0x15 at E:\UnitySrc\unity-trunk\Modules\UIElements\Core\Panel.cs:[1604:13-1604:27]    C#