InvalidateControl in Excel not working... not sure what I'm doing wrong

Question

Thank you for taking the time to read my question.

I have an EditBox in my ribbon that I want to clear after a button is clicked (also in the ribbon).

I have this at the top of my module:

Dim MyRibbon As IRibbonUI

Sub MyAddInInitialize(Ribbon As IRibbonUI)

Set MyRibbon = Ribbon

End Sub

And this is the code that I'm having issues with. When I click my button and call Sub CommandButton16 (or 17) I want the last thing it does to be clearing 2 EditBoxes. So far just trying to clear the one.... but I'm getting the error shown in the screen.

What am I doing wrong?

Above is the XML from Office RibbonX Editor pertaining to my buttons that do stuff, then I want them to clear the editBoxes after.

Thanks!