I've looked at the properties of the elements, and the code blocks, and even changing code etc, and I cannot seem to figure out why this one student's Map Tour App is zooming out every time until it cannot zoom any longer when using the Destination Listpicker or the My location button. But the zoom slider works as expected...
I tried it on her iOS phone, my iOS phone, and an Android tablet. My device works fine with all the other students' apps
Thank you!
ZoomIssueMapTour.aia (3.6 KB)
Oh and I enabled the zoom + and - and those work correctly...
some ideas that might ameliorate some of your student's issues. Here solution is certainly not conventional use of the ListPicker.
The zoom issue "zooming out every time until it cannot zoom any longer when using the Destination Listpicker or the My location button might be due to here un-conventional of the LP.
- I found that the slider was too close to the Map. Sometimes when I select slider, I drag fingers to other parts of the screen. I.E. the Map, the Destination button, the Map TypeButton, MyLocation. When any of these are 'selected' accidentally, you have problems. Partial solution is to move the slider away from the map. I used a Label and set its height to 10% of screen height
Also of note is if you select Areal or Terrain for the map type the user cannot return to Roads. This behavior started happening about a month ago. Short story, it you select anything but Roads, user cannot later return to Roads. This appears to be an OpenStreetMap issue. Solution is not to allow any type except Roads until MIT finds a solution. I un-abled the MapType Button.to prevent use of the Button. 
This may only be an issue with Android 13 and 16 (I have 13); see Map NOT displayed - #2 by TIMAI2
Also these are complex ways of selecting from a List Picker. Doing so may be creating issues regarding timing and settings on other controls.. Simpler to select from a List
