About a year ago, bug #TAP-5-869 was about the usage of submit buttons with context in loops. The bug was closed because using the defer parameter of the submit button fixed the problem.
Now I have the same problem, but this time in a Grid rather than a loop component. Defer is set to false but every time I click on a button, only the context of the last one is used.
I created a small example demonstrating the problem, I will attach it to this bugreport. Try clicking on every user and watch the console output: Always the last user is printed.