Hello Ray,

Thank you for the additional information.

This behavior is expected and let me explain why: The RadComboBox control contains RadEntry inside. When you have an implicit Style for the RadEntry and having a BorderBrush and thickness set, this style is applied to all RadEntry controls. Including this in the RadComboBox. So the behavior in 4.0.0 version was wrong. 

Here are the elements and the border applied:

To avoid that behavior I could suggest you use explicit style to the RadEntry(x:Key) or inside the ComboBox Loaded Event set the BorderThickness of the inner RadEntry to 0:

private void combo_Loaded(object sender, EventArgs e)
{
    var combo = sender as RadComboBox;
    var entry = VisualTreeElementExtensions.GetVisualTreeDescendants(combo).First(x => x is RadEntry) as RadEntry;
    entry.BorderThickness = new Thickness(0);
       
}

Here is the result:

I hope I was able to explain the situation. I changed the item status to "Declined" as this is not an issue in the control. 

Regards,

Maria
Progress Telerik

Hi,

I have tested the behavior of RadComboBox on Visual Studio 2022 official (17.4.4) with .NET 7, on Windows 11 and I cannot reproduce the extra border behavior.

Here is the result:

Could you please share whether the behavior happens only when Visual Studio preview is used? Have you tried the official version? Also for the test, I used the latest Telerik .NET MAUI version 5.0.1.

I am looking forward to your answer.

Regards,
Maria
Progress Telerik