I found the following properties aren't saved after the add datasource request although for some of them the code that writes them to the xml is there (the properties are just missing from the model being saved, although I made sure that they were received and read in DataSourceModelNodeUtil)

Common props:

exception-sorter-properties
stale-connection-checker-properties
valid-connection-checker-properties
reauth-plugin-class-name
reauth-plugin-properties
security-domain
flush-strategy
set-tx-query-timeout
use-ccm

XA:

interliving
all recovery properties

is-same-rm-override is written twice, i.e.

<is-same-rm-override>
true
</is-same-rm-override>
<is-same-rm-overide/>