The document window contains the canvas, where the screens, basic elements and widgets are displayed.
You can open multiple document windows at a time. Every document window has a tool bar that contains most often used functions.
You can customize the toolbar by choosing "Customize Toolbar…" from the toolbar's contextual menu.
Below the toolbar, the style bar is located. The style provides quick access to styling and layout options of selected elements.
On the bottom of the window, the status bar shows the hierarchy of the selected and element. There you can also change the zoom level and switch between breakpoints.