Page/Blog: content can not be deleted after preview is opened, content changes cancelled and page refresh not done

[daivabrazukaite]

Open any page/blog -> open for edit some content -> click on Preview: preview will be opened (ok). Cancel edit modal -> choose to delete just viewed content: error "The record was updated by another user" will be presented and content could not be deleted until page reloaded.
Example of error received in logs:
2016-03-15 09:33:51.4025 Failed to execute command DeletePageContentCommand. Request data: BetterCms.Module.Pages.Command.Content.DeletePageContent.DeletePageContentCommandRequest.
HtmlContent with id 100a716b-825f-440f-b863-a5ca009d8996 Entity was updated by another transaction. BetterModules.Core.Exceptions.DataTier.ConcurrentDataException: HtmlContent with id 100a716b-825f-440f-b863-a5ca009d8996 Entity was updated by another transaction.
at BetterCms.Module.Pages.Command.Content.DeletePageContent.DeletePageContentCommand.Execute(DeletePageContentCommandRequest request)
at BetterCms.Module.Root.Mvc.CommandHandler.ExecuteCommand[TRequest,TResponse](ICommand`2 command, TRequest request)