prs/prs.desktop/DockPanels/Problems/ProblemsDock.xaml

<UserControl x:Class="PRSDesktop.ProblemsDock"
             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://schemas.microsoft.com/expression/blend/2008"
             xmlns:local="clr-namespace:PRSDesktop"
             mc:Ignorable="d"
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
        <!-- <local:ProblemsDockGrid x:Name="problems" /> -->
    </Grid>
</UserControl>