Avoid Windows 'Ding' when Enter is pressed in TextBox with OnKeyUp

If a user hits enter in a windows forms textbox with a KeyUp Event, windows sounds a beep or ding. I could not determine why this happens and how I could avoid this.

Any help would be appreciated.

I imagine this is caused by a combination of:

• MultiLine = false
• No default button on the form

because single-line textboxes forward the enter key to the default button. The ding is generated when a default button can't be found.