Duplicate workitem selection dialog does not show

Once we change the workitem to closed state with Duplicate as resolution, an error link shows up and on clicking it should open the dialog box to select the duplicate workitem. But for one of the project area, for task and feature workitem types the dialog box/window does not show up(it does nothing) on clicking the error link and on same project area it shows up for problem/defect. I have compared template for all types and did not observe any differences. Please let me know in case I have missed any change.

Thanks,

Vinay