There are four kinds of toolbars in the Workbench.
The main toolbar, sometimes called the Workbench toolbar, is displayed at the top of the Workbench window directly beneath the menu bar. The contents of this toolbar change based on the active perspective. Items in the toolbar might be enabled or disabled based on the state of either the active view or editor. Sections of the main toolbar can be rearranged using the mouse.
There are also individual view toolbars, which appear in the title bar of a view. Actions in a view's toolbar apply only to the view in which they appear. Some view toolbars include a Menu button, shown as an inverted triangle, that contain actions for that view.
A third type of toolbar is the perspective switcher. The perspective switcher allows quick access to perspectives that are currently open. It also has a button that can open new perspectives. The perspective switcher is normally located in the top-right, next to the main toolbar. However, it is also possible to position it below the main toolbar ("top-left"), or to position it vertically on the left-hand side of the workbench ("left"). The name of the perspectives is shown by default, but it is possible to hide the text and show only the icons. To reposition the perspective or hide the text, right-click on it and choose the appropriate item from the context menu.
Minimizing a view stack will also produce a toolbar in the trim at the outer edge of the workbench window (a Trim Stack). This bar will contain an icon for each of the views in the stack. Clicking on one of these icons will result in the view being displayed as an overlay onto the existing presentation.
In all cases, you can find out what toolbar buttons do by moving your mouse pointer over the button and reading the tooltip that opens. See the list of related reference topics below for a table of all toolbar buttons.