By default when we use "Group By This Field" the grouped column will be hidden, so it will not be possible to use "Ungroup This Field" without showing the Group box.

However we already have a property to show the column even if it is grouped, please set the HideColumnsWhenGrouped property to no under LayoutSettings. After showing the grouped column in the WebGrid header the option "Ungroup This Field" will be available for the grouped column

That's not a very good solution.  Why would we want to show the column when it's grouped?  This can easily be implemented since you have to already know what the grouped column is in the grouped header row.  It would make more sense to be able to click on any grouped header row and select ungroup.  It's nice to have this available on the column, but we wouldn't want to see the column in group mode.

I'll try this and see how it works, but I'm sure management isn't going to like having that column shown.  Thanks.

I will create a feature request which allow user to ungroup grouped column using column header context menu while the grouped column is not shown to allow an implementation of this feature in future release of WebGrid.