remove red rectangle around combobox

Question

i need to remove red rectangle around combobox. I have setup combobox in xaml like (below) this and i`m trying to override of the Validation.ErrorTemplate.

Answer 1

The setter in your trigger is setting the Visibility property of an element named "NotValid". That is not defined in the XAML you posted. If there is no element named "NotValid", that is your problem.