1. What is the problem? Be very detailed.
I have A list of schools to be visited and inspected but i need it to be selected only 1 item per form , any way to achieve that so if any one select item ,the second employee cant select it , or have an indicator that its selected before
2. What app or server are you using and on what device and operating system? Include version numbers.
latest copy of collect and Aggregate
3. What you have you tried to fix the problem?
search all over manual and cant find it
4. What steps can we take to reproduce the problem?
fill list of drop down (A/B/C/D), answer form , With select A , next time A Expected to be not shown
unfortunately it's not possible to do that unless it's just one form. You can't just get answers from all already filled forms to determine which options should be used in the current one.
This is the kind of thing that the relatively new last-saved-instance feature is designed to enable if all data collection happens on a single device. This has not yet been officially announced because there is no XLSForm support yet. I believe the last bits of the specification have just been approved so this should come relatively quickly now. Note that this is not hugely performant and has some limitations.