禁用WPF TextBox中的覆盖模式（按Insert键时）

When the user presses the Insert key in a WPF TextBox, the control toggles between insert and overwrite mode. Usually, this is visualised by using a different cursor (line vs. block) but that's not the case here. Since there is absolutely no way for the user to know that overwrite mode is active, I'd simply like to disable it completely. When the user presses the Insert key (or however that mode could possibly be activated, intentionally or accidently), the TextBox should simply stay in insert mode.When the user presses the Insert key in a WPF T