Always use master language first.

frontend/app/features/content/pages/content/content-page.component.ts

@@ -93,7 +93,7 @@ export class ContentPageComponent extends ResourceOwner implements CanComponentD
             this.languagesState.languages
                 .subscribe(languages => {
                     this.languages = languages.map(x => x.language);
-                    this.language = this.languages[0];
+                    this.language = this.languages.find(x => x.isMaster)!;
                 }));
 
         this.own(

frontend/app/features/content/pages/contents/contents-page.component.ts

@@ -106,8 +106,7 @@ export class ContentsPageComponent extends ResourceOwner implements OnInit {
             this.languagesState.languages
                 .subscribe(languages => {
                     this.languages = languages.map(x => x.language);
-                    this.language = this.languages[0];
+                    this.language = this.languages.find(x => x.isMaster)!;
-                    this.languageMaster = this.languages.find(x => x.isMaster)!;
 
                     this.updateModel();
                 }));