There is a bugfix, they call it a Hotfix, I don't know what that means, update to ArchiCAD. The updater is on the Onion in ArchiCAD Program Files. It's called AC9-1965.
Everyone should run this. You can run it from the Onion, rather than copying it to your machine.
(You can check for updates any time by choosing Check For Updates from the Help menu in ArchiCAD.)
Here is the list of fixes. Most of them don't mean much to me, hopefully some of our (unlisted) issues have been fixed too.
It has been out for several days and no one has complained yet, so it probably does no harm.
Graphisoft's version numbering scheme has become completely ridiculous. Patches like this one should increment the third digit in the version number, making this 9.0.1. But no, they have this quirky "v1, v2" patch numbering deal, but they don't even use that consistently. Sometimes a patch increments the v number, sometimes it adds a "+", and in this case it does nothing, it's still v1. So it's not 9.0.1, it's not 9.0.0 v2, it's not 9.0.0 v1+, it's 9.0.0 v1 Build 1965. You have to know the build number, which should be a really geeky arcane thing, in order to describe the standard current release of the program. Most people outside of software development don't know what a build number is. Ridiculous.