I want to placed an object from the standard Archicad library but it it greyed out from the Obejct Default Settings windows. Here's an screen shot. I can navigate through the folders but I can't choose the objects.
Thank you very much for the report and I am very sorry for the issue!
I agree with the comment above: it's worth checking the Library Manager (File > Libraries and Objects > Library Manager...) for more information. It is possible that the Library's path is not valid anymore. Maybe it was deleted or replaced to another location. I would suggest re-adding the Libraries and see if that solves the issue.
If it was not related to the case, I suggest reaching out to the local support for further investigation.
I tried removing the library and re-adding it back in. Though, probably another unrelated issue, in some teamwork files, upon opening the teamwork file, the some library objects are again missing. Upon inspection, it was the object that were in the embedded library.