I had a look at Manjaro LXDE 16.03 released a few days ago. This is using Openbox 3.6.1. and Abiword 3.0.1 so the same as for Lubuntu Xenial. This bug was not present in the live session. Checking the version of Abiword in Manjaro LXDE there was no error message, but for L. Xenial the attached error was shown. So maybe this bug is not an Openbox nor Abiword issue.
I had a look at Manjaro LXDE 16.03 released a few days ago. This is using Openbox 3.6.1. and Abiword 3.0.1 so the same as for Lubuntu Xenial. This bug was not present in the live session. Checking the version of Abiword in Manjaro LXDE there was no error message, but for L. Xenial the attached error was shown. So maybe this bug is not an Openbox nor Abiword issue.