I had a similar issue too, I could interrogate the ok button on the message box that popped up from web window, button click performs ok when I try the test methods during interrogation, (although the message says Event GotFocus and Event LostFocus). However it doesn't work fine while the project runs on.
Thank you for posting your query in the PSC. This looks like an inactive post and hence, we suggest you create a new post for your query. Click on the Write a Post button that’s available on the top right pane of this page. Once created, please reply back here with the URL of the new post.
You may also refer this discussion link as a reference in the new thread.