edit

XLAB2/SelectInstrumentTypeWindow.xaml

@@ -61,14 +61,17 @@
         </DataGrid>
 
         <StackPanel Grid.Row="3"
-                    Margin="0,10,0,0"
-                    Orientation="Horizontal">
-            <TextBlock Width="150"
-                       Margin="0,0,8,0"
-                       VerticalAlignment="Center"
-                       Text="Заводской номер" />
-            <TextBox Width="320"
-                     Text="{Binding SerialNumber, UpdateSourceTrigger=PropertyChanged}" />
+                    Margin="0,10,0,0">
+            <TextBlock Text="Заводские номера" />
+            <TextBlock Margin="0,4,0,0"
+                       Foreground="DimGray"
+                       Text="Перечислите номера через запятую, точку с запятой или с новой строки." />
+            <TextBox Margin="0,6,0,0"
+                     Height="96"
+                     AcceptsReturn="True"
+                     TextWrapping="Wrap"
+                     VerticalScrollBarVisibility="Auto"
+                     Text="{Binding SerialNumbersText, UpdateSourceTrigger=PropertyChanged}" />
         </StackPanel>
 
         <TextBlock Grid.Row="4"