once change label text colour it didn't change again! what to do?

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C#

I have wrote a password validation method which check existence of minimum 8 characters in password along with minimum 1 uppercase, 1 lowercase, 1 numeric and 1 symbolic character in it. if password is valid then it return a string "Good Password" else return "Week Password". and its working very fine.

Now when i get this string and do following action of code on password text box

private void txtPassword_KeyUp(object sender, KeyEventArgs e)
        {
            string password = txtPassword.Text;
            lblValidation.ForeColor = Color.Red;

            string passValidation = ValidatePassword(password);

            if (passValidation == "Good Password")
            {
                lblValidation.ForeColor = Color.Green;
                lblValidation.Text = passValidation;
                lblPasswordInstructions.Visible = false;
            }
            else
            {
                lblValidation.Text = passValidation;
                lblPasswordInstructions.Visible = true;
            }
        }

lblValidation didn't change its colour from red to green. also lblPasswordInstructions didn't hide itself just "Good Password" and "Week Password" are shown with red in colour.