Note: this problem is reproducible with RadTextBoxControl as well. The Enter and Leave events also don't fire when RadTextBoxControl is inside a RadPopupContainer Resolution: Case 1: RadTextBoxElement is not a control and do not have validation events. Use RadTextBox with RadMenuHostItem instead: RadTextBox tb = new RadTextBox(); RadMenuHostItem item = new RadMenuHostItem(tb); tb.Validating += Tb_Validating; item.MinSize = new Size(50, 20); radMenu1.Items.Add(item); Case 2: RadPopupEditor has message filter which is responsible for closing the popup and it intercept the leave and enter messages. Use GotFocus and LostFocus instead.