Dividing and combining rows
 

I learned by experimentation that CTRL Return will establish a new row cell at the cursor, thereby dividing the original row into two rows. I am unsure if this is in the manual, but it is VERY useful.

I would also like to be able to do the reverse of the above, namely, select two cells in the same columns of adjacent rows and combine them into a single cell. Of course, this can be done by cutting and pasting text, but I'd like to do it with a single key command. Is this possible in OmniOutliner?

I think ctrl-delete will approximate what you're trying to do (put the cursor in front of the row you want to join to the one above)