batch change of selected columns/rows
 

I am using kGTD, and have a bunch of tasks with metadata in columns (namely, context, start date, etc.). I have not discovered a way to make batch changes to a selected group of rows' column info in OmniOutliner.

Let's say I have 10 tasks whose context is "deferred+", and I want to change those items' contexts to "@office".

Or: I have 20 tasks which have various dates in the "Due Date" column, and I want to erase all of the dates in one fell swoop, as a batch, so that I don't have to manually edit and erase each row's "Due Date" info.

Any help would be greatly appreciated.