The type 'UserControl' does not support direct content
I have an Outlook 2013 and 2016 VSTO Add-in project and am trying to add a WPF user control to a custom task pane as described here . The problem I have is when I add the User Control (WPF) it generates me a WPF control with a grid, but automatically throws an error of "The type 'UserControl' does not support direct content". WPF generated: <UserControl x:Class="TestNamespace.UserControl1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http:/