text: Title: Changing a value of a widget placed below other widgets triggers their re-rendering if another one used of the same type
  Body: Place two widgets of the same type (dropdown) in two different cells separated by a cell which prints a message with a counter.
  If the upper one value is changed, all of them are re-rendered (ok) but if the lower one is changed, it's still the case, even if it should not. I suspect it has to do with the fact that these two widgets are of same type, and there is no unique identifier or something.