Merge remote-tracking branch 'origin/dev-v7' into dev-v7.7

# Conflicts:
#	src/Umbraco.Core/Models/UserExtensions.cs

src/Umbraco.Core/Models/UserExtensions.cs

@@ -4,6 +4,7 @@ using System.Globalization;
 using System.Linq;
 using System.Net;
 using Umbraco.Core.Cache;
+using Umbraco.Core.Configuration;
 using Umbraco.Core.IO;
 using Umbraco.Core.Models.Identity;
 using Umbraco.Core.Models.Membership;
@@ -109,7 +110,7 @@ namespace Umbraco.Core.Models
             catch (CultureNotFoundException)
             {
                 //return the default one
-                return CultureInfo.GetCultureInfo("en");
+                return CultureInfo.GetCultureInfo(GlobalSettings.DefaultUILanguage);
             }
         }
 

src/Umbraco.Web/Editors/BackOfficeController.cs

@@ -161,7 +161,7 @@ namespace Umbraco.Web.Editors
                 ? Security.IsAuthenticated()
                     //current culture is set at the very beginning of each request
                     ? Thread.CurrentThread.CurrentCulture
-                    : CultureInfo.GetCultureInfo("en")
+                    : CultureInfo.GetCultureInfo(GlobalSettings.DefaultUILanguage)
                 : CultureInfo.GetCultureInfo(culture);
 
             var textForCulture = Services.TextService.GetAllStoredValues(cultureInfo)