[Solution] Android Studio does not displays Toolbar in Layout Design

For an App template that you select when you create an Android App in Android Studio, it has a Toolbar, but when you open the layout.xml file in Design mode you would have noticed that it does not display the Toolbar.

In order to enable the Toolbar, open your layout fine and go-to design and click on the eye icon and from the dropdown select - "Show System UI"

Note: This option may be different if you are using older versions of Android Studio

Tested on: 
Android Studio 4.1.3
Build #AI-201.8743.12.41.7199119, built on March 11, 2021
Runtime version: 1.8.0_242-release-1644-b3-6915495 x86_64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
macOS 10.16
GC: ParNew, ConcurrentMarkSweep