What to do when WPF Window doesn't recognize user control defined in the same project

<Window x:Class="TCI.Indexer.UI.Operacao"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:tci="clr-namespace:TCI.Indexer.UI.Controles"
    Title=" " MinHeight="550" MinWidth="675" Loaded="Load" ResizeMode="NoResize" WindowStyle="None" WindowStartupLocation="CenterScreen" WindowState="Maximized" Focusable="True">
    <Canvas Name="canv">

        <tci:Status  x:Name="ucStatus"/>
        <Grid Canvas.Top="0" Canvas.Left="0">

            <StackPanel Orientation="Horizontal">
                <!-- Indices -->
                <Label Width="200"/>

            </StackPanel>
        </Grid>
    </Canvas>
</Window>