The dashborad widget "Top hosts" stops displaying values in column, that is based on Item that has been renamed in Template.

Steps to reproduce:

1. Create dashboard with widget "Top host" and display column based on some numeric Item.
2. Rename the Item in Template (item key will left untouched)
3. The widget stops displaying content.
4. Modify widget configuration for the affected column, unselect Item a select it (with new name) again - dashboard will work again.

Result:
See screenshot after item rename

See screenshot after widget reconfiguration (step 4 above)

Expected:
Widget is able to reflect Item name change in its configuration.