Attribute o:ogfxdata
is poorly documented in the web.
According to your investigations, it's some kind of compatibility extra information.
You can delete those attributes in your template using OpenTBS. The cleaning can be done once on your template without any merging, and then save the cleaned template as a new template. Or you can perform the cleaning each time you open the template.
Cleaning the DOCX file:
while ($x = clsTbsXmlLoc::FindStartTagHavingAtt($TBS->Source, 'o:gfxdata', 0) ) {
$x->ReplaceAtt('o:gfxdata', '');
$TBS->Source = str_replace(' o:gfxdata=""', '', $TBS->Source);
}
Note that the class clsTbsXmlLoc
is provided with OpenTBS and is undocumented.
The code should work since OpenTBS 1.8.0. (which is currently in stable beta version).
I've noticed that since attributes o:gfxdata
are deleted, they do not come back immediately when you edit the docx.