Not showing text in designer when use converter

[Genusatplay]

When use binding
<TextBlock Text="{Binding Source={l:Static p:Resources.UserFiles}, Path=Translated, Converter={x:Static converters2:StringTestConvUp.Default}}" />
textblock in xaml designer collapsed
In runtime works fine.
VS2019 with resharper show warn

vs think source is string

how i can setup right context for it?