U4-4198, adding a hidden field in the related links property editor to maintain the title property when editing. This will be mapped directly to the caption property value.

src/Umbraco.Web.UI.Client/src/views/propertyeditors/relatedlinks/relatedlinks.html

@@ -15,6 +15,7 @@
                 <td style="word-wrap:break-word; word-break: break-all">
                     <span ng-show="!link.edit">{{link.caption}}</span>
                     <input type="text" ng-model="link.caption" ng-show="link.edit" />
+                    <input type="hidden" ng-model="link.title" value="{{link.caption}}" />
                 </td>
                 <td style="word-wrap:break-word; word-break: break-all">
                     <div ng-show="!link.edit">