Weird Textbox_Exit procedure behaviour

I have a form with a couple of controls on it including a frame. In this frame is a couple of textboxes where the user must enter some dates. I want to add error checking to this textboxes to make sure an incorrect/invalid date is not entered. I wanted to add error checking to the Control_Exit procedure to check for incorrect/invalid dates.

Problem: If I click in any one of the textboxes (all blank at this stage) other than the first textbox in the frame the first textbox Exit procedure is run and then the procedure crashes because there is no valid date in the first textbox. I can't even get to my error checking as it crashes before that (Runtime error 13. Type mismatch.). Even though this textbox was not selected at all

I tried changing the tabindex of the controls to make another textbox the first one and then it crashes on the new first textbox

Any idea why this is happening? Why would the Control_Exit procedure run without the control being selected first?

A Frame control is a container and behaves the same way a userform or other container does - as soon as you set focus to it, the control with the lowest tab index gets the focus. So when you click another textbox, you set focus to the frame first, which sets focus to the first textbox and then the focus moves to the control you actually clicked.

With all that said, your code should be checking for an empty control first.

That explains a lot. Thank you.