@vfiddes I have asked for this in the past too... I think it has to do with how App Lab works overall and from an engineering perspective, it is more difficult than I thought it would be to get the numbers to show up after the program is done running. I will check again that this is still the case.
I just have students put their finger on where they want something to be, then re-set the screen and get the coordinates at that point. Sometimes they have programs that are REALLY long to run, in which case we talk about testing out a smaller part in another space or commenting out a chunk of code so that the part they want to focus on only runs.