What is a "Toolbox" in an Application?
A toolbox is a panel or floating window that contains tools that can be selected (activated). The difference between a toolbox and a toolbar is that tools in a toolbox are typically modal: there is always one tool selected, and activating one tool deactivates the other. In other words, the toolbox controls what "mode" of operation the application is currently in. Toolboxes are commonly seen in image editors such as Krita and Photoshop.
By convention, tools in a toolbox can be activated using keyboard shortcuts, generally not chords, but single keys. For example, the "brush" tool may be the key B, and the "text" tool T. Hovering over a tool should display its tooltip that contains which hotkey is currently associated to that tool.
In some applications, a single tool icon may feature a dropdown arrow that displays multiple tools pertaining to a single group (e.g. bucket fill and gradient fill may be separate tools grouped together).
