Trying to capture <span>text</span> that quickly disappears from the page

One way would be to confirm that the Apply Changes button is gone

This is a good idea. => You can use the VisualSearch command to wait for a button to disappear.

Actually in your case - because everything goes so fast - you do not have to wait at all (so no RepeatIF loop needed).

You can just verify that the “Apply changes” button is really gone. In below code visualSearch searches up to 5 seconds for the button, and if none is found, returns 0.

  • store | 5 | !timeout_wait reduce wait time
  • visualSearch | Image_of_ApplyChangesButton.png | found
  • if | ${found} == 0 | .... - verify that the button is not visible.

Another option is to extract the color of the area where the button should be and make sure the color is black (=> so no button visible).