In my project, initially I configured the active sprint columns as pending, ongoing, dropped and done( 4 columns). However with this configuration, the sprint closure is not possible. Sprint is not allowed to close with tasks/subtasks under dropped column ! Strange.
Then after, I merged dropped in to done with 3 column configuration, then the closure is possible. The concern is, the drag and drop is bit tricky. Engineers by mistake drop their sub tasks to dropped instead of done as both are configured in the same column.
My question is can you program to allow closure of sprints with a dedicated "dropped" column having tasks in it?