Premiere Bro Blog wrote this great article that thoroughly explains working with workspaces in Adobe Premiere Pro.
WORKING WITH WORKSPACES IN PREMIERE PRO
May 25, 2017
MANAGING AND TROUBLESHOOTING PREMIERE PRO WORKSPACES
One of Premiere Pro's greatest strengths is its fully customizable interface. Workspaces give video editors the freedom and flexibility to arrange Premiere Pro's layout to accommodate their editing workflow. It's important to understand the inner workings of workspaces if you want to work faster in Premiere Pro
There has been some odd workspace behavior in Premiere Pro CC 2017. Some users have noticed clicking on the Titles workspaces does absolutely nothing. Other users can't find the default Graphics workspace.
This in-depth blog post will help editors understand how to manage Premiere Pro workspaces and troubleshoot unresponsive or missing workspaces. But first, a quick overview of workspaces and how to edit them.
WHAT ARE WORKSPACES?
The Premiere Pro interface is made up of panels that are organized into a layout, and saved as a workspace. Premiere Pro comes with 9 factory-default workspaces: Assembly, Editing, Color, Effects, Audio, Libraries, Graphics, All Panels, and Metalogging. You can see by their names that Adobe has arranged the default workspaces by specific post-production tasks. Not a bad strategy for customizing your own Premiere Pro workspaces.
Learn more about Premiere Pro workspaces.
The list of all the panels in Premiere Pro (including extensions) can be found under the Window menu. If you've accidentally closed a panel, the Window menu is where you can find it. All of these panels can live in the interface wherever you want to put them. Click and drag a panel tab to dock it, or add it to a panel group indicated by the purple drop zones.
Click here to read the full article on Premiere Bro