Yup it's highlighted when I follow those steps.
Full steps for me are as follows:
generate dialog
enter text in text field
click outside text field, on the dialog, to trigger button activation
right click namemapping item and choose highlight, button control is highlighted onscreen.
Please show how your element is presented in Object Browser (including its properties).
Screenshot attached
Hm... Strange...
Can you please also provide a screenshot of the relevant piece of your keyword test where the reference to the button is obtained and the button is clicked then?
Here you go
