The window toolbar lets you quickly access all of the additional design windows available in Blocs such as the Class Manager, Asset Manager, Swatch Manager, Menu Manager and Project Notes.

The window toolbar is located at the bottom of the inspector sidebar. To open one of the additional windows, simply Left Click the relevant icon. This will cause it to become highlighted indicating that the window is now open, alternatively a Left Click on an already highlighted icon will cause the relevant window to close.