Waiting until Button is not ’Greyed out’

[Undead_Fox]

 
I have a program which I have built a task to use it automatically but at one point a Button is greyed out and stays that way until a scan is finished - you then click on this button to go onto the next stage.  I am a complete beginner on this - how do you get RoboTask to wait until the button is not greyed out before it is clicked ?