DEVONthink uses the somewhat minimalistic RTF table widget that OS X provides (See Format > Table). It is not possible to insert a row inside the table – insertion only occurs at the end of the rows or columns, as the case may be.
To do what you’re looking to do, open the RTF externally (Data > Open With) in a more feature-rich RTF editor – Pages, Word, Mellel, Bean, Nisus, etc.
I tried the method “Data -> Open with”
with three of your recommendations to edit a table in a RTF:
bean -> works OK
melle (trial version) -> it always saves the modified
rtf file to a directory on the Mac.
For bean, after clicking ‘Save’,
the display in DevonThink (DT) shows the
updated content.
Pages -> not tried after browsing Apple’s web site.
It says it could not save to rtf.
Also tried Ominoutliner (OL) for the imported .oo3 file:
–> I can edit the content by OL and click ‘save’ and DT shows
immediately the updated content.
However,
DT displays the Date Column incorrectly.
7/30/2015 in OL shows up as M/d/yy in DT
This may be a known problem ?