1. Have optimistic locking enabled for the work objects. For enabling this feature, navigate to case type rule and in Advanced tab, select "Locking". Now configure optimisitic as the case locking mechanism. Default case locking is something where when one user is working on the case, other user is not allowed to work on the same case in parallel and is provided with a message. And optimisitc locking is mechanism is where both users get a chance to work on the work object parallely and the user who clicks on "Submit" (finishes the assignment/commit is performed) first obtains the lock. Suppose userB has clicked on submit first and now user A clicks on submit, then user A is notified with a message. 2. Create or modify timeout/locktimeout DSS setting to set the value in minutes after which the lock has to be released.
Thanks for reply, i have tried on Top level case type with Default option by entering the number of minutes in the Release Lock after field to override the default value. This doesn't help us in resolving the issue.