The toolbox is Synfig's main window - you can have several canvases open, but only one Toolbox. If you're familiar with software like The GIMP, you'll recognize this approach (as opposed to say, an MDI, or a permanently-docked canvas window).
Features of the Toolbox:
This category has only the following subcategory.
Pages in category "Toolbox"
The following 2 pages are in this category, out of 2 total.