Problem incomplete display of items in a combobox WPF C# strange issue?

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WPF

combobox

DataGrid

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I'm using wpf c# and Entity Framework

I have a DataGrid on that show data from database

when users click on datagrid that row will show items in ComboBox (Load on of columns in combobox)

but problem is combobox doesn't show Normal list
https://i.stack.imgur.com/vIj3u.png[^]

Code Behind CS :

DENAF1399Entities dbms = new DENAF1399Entities();

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    var qre = dbms.Database.SqlQuery<Q_View>("SELECT * FROM Q_View");
    datagrid1.ItemsSource = qre.ToList();
}

private void datagrid1_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
    Q_View QVkala = datagrid1.SelectedItem as Q_View;
    if (QVkala != null)
    {
        combobox1.ItemsSource = QVkala.NAMES;
    }
}

What I have tried:

I tried

-Change Fonts of combobox

-use new combobox

but didn't work

please help me