NSGridView merge cells in storyboard

How do you merge cells in an NSGridView in the storyboard editor? I can select contiguous cells in a row using left mouse + ⌘, but I haven't found a menu selection (or other) to merge the cells.

This video from WWDC 2018 mentions that your can merge cells like you do in the Numbers spreadsheet app. (approx the 32:30 mark)

https://developer.apple.com/videos/play/wwdc2018/209/

Help is appreciated!

Accepted Answer

Select cells to merge

Click small disclosure button in column/row header

Select Merge

image @ stackoverflow
NSGridView merge cells in storyboard
 
 
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