Lowercase "HDR" in the editor config for consistency, as everything else is lowercase as well.

bin/Data/Scripts/Editor.as

@@ -250,7 +250,7 @@ void LoadConfig()
         if (renderingElem.HasAttribute("dynamicinstancing")) renderer.dynamicInstancing = renderingElem.GetBool("dynamicinstancing");
         if (renderingElem.HasAttribute("framelimiter")) engine.maxFps = renderingElem.GetBool("framelimiter") ? 200 : 0;
         if (renderingElem.HasAttribute("gammacorrection")) gammaCorrection = renderingElem.GetBool("gammacorrection");
-        if (renderingElem.HasAttribute("HDR")) HDR = renderingElem.GetBool("HDR"); 
+        if (renderingElem.HasAttribute("hdr")) HDR = renderingElem.GetBool("hdr");
     }
 
     if (!uiElem.isNull)
@@ -385,7 +385,7 @@ void SaveConfig()
 
     renderingElem.SetBool("framelimiter", engine.maxFps > 0);
     renderingElem.SetBool("gammacorrection", gammaCorrection);
-    renderingElem.SetBool("HDR", HDR);
+    renderingElem.SetBool("hdr", HDR);
 
     uiElem.SetFloat("minopacity", uiMinOpacity);
     uiElem.SetFloat("maxopacity", uiMaxOpacity);