The themes or layouts are all built-in, UHF. Start DAZStudio. Go to Window-->Workspace-->Select Layout.  Also, go to Window-->Style-->Select Style. There are other things in there, too, that may help, such as Window-->Panes (Tabs), and Window-->ViewPorts. But I think the first two of these will help. 

Change the Layout or Style. That may bring back all the Graphs, etc., that should be there.

Sometimes weird things happen after going up to the next release, although I do find 4.5.1.56 to be running pretty well. I had never been able to get Smart Content, and after I upgraded, nope, still no smart content. I tried "reimporting metadata," but nothing.

Then, the next day, I tried once again, to reimport metadata, and, it suddenly worked! Now I have Smart Content. Maybe the memory of the computer needed to be cleared out or something. Shutting down and letting the memory drain may help. Then, try the same things later.

 

To Import Metadata, go to your Content Library tab, and you'll see a little triangle at the top pointing to the right. (It's over on the top left edge of that tab.)  Click on it, and pull down to Content DB Editor or Content DB Maintenance. You might try "resetting the Content DB." Then, you might try "Reimport Metadata." Make sure, of course, that your Content DB Manager is running.