Options > Element Attributes > Markup-Styles gives the attached dialog to reserve these attributes if you or ED need to create new styles. (My file had already been used with ED before sharing, so the attributes already exist in the shared file.)
I'm glad I looked - I thought that these were in Attribute Manager as well. Strangely, they are not ... so I have no idea how one would export/import these style attributes, but that is off topic...
Looks like the Markup entries themselves belong to whoever creates them, so not a reservation issue.
But, I'm guessing that all building shell elements (walls, slabs, roofs) need to be reserved so that ED can assign markup styles to them as it or you categorize them.
Short of me playing - there must be someone out there who has used ED with TW?
Cheers,
Karl
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB
One of the forum moderators