I'm using AC20 Build 3012 (full commercial version) on a PC with Windows 10. For whatever reason, I don't have the tab bar so I have to keep switching back and forth between views through the "Window" menu.
Typically you'd get your tab bar by going to Window>Show/Hide Tab Bar, and you can set your tab bar preferences under 'More Options' in your work environment settings.
Neither of these options are available to me. It's not that they're greyed out, they're just literally not in any of the menus.
The Show/Hide Tab Bar command could be missing from your Work Environment (particularly if your WE was imported from an earlier version), so check Work Environment > Command Layout Schemes > Menus > Window to see if it is there. The current AC20 build is 8005, the Library Build Number is 3010.2, so check if your build is up to date.
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.
Yes, just load the standard 20 Work Environment.
Try not to use custom WE from older versions, as the new commands may be missing.
It is best to re-create your custom WE for each version if you need to.
One of the forum moderators. Versions 6.5 to 25 Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10 Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10