Desktop applications have provided Contextual Tools for a long time in the form of Secondary Menus. These menus have been rare on the Web. Google Maps uses a secondary menu that is activated by a right-click on a route. It shows additional route commands (Figure 4-25).
Figure 4-25. Google Maps uses a right-click menu to add new route stops or to adjust the map around the current point on the route
One problem is the browser inserts its own right-click menu. Replacing the menu in normal content areas can confuse users, as they may not know if the standard browser menu or the application-specific menu will be shown. It will depend on whether it is clear that an object exists in the interface (as in the route line above), and if the menu is styled differently enough to disambiguate the menus.
As a general rule, never put anything in the Secondary Menu that can't be accomplished elsewhere. Secondary Menus are generally less discoverable. More advanced items or shortcuts, however, can be placed in the Secondary Menu as an alternate way to accomplish the same task.
Right-click is not the only way to activate a Secondary Menu. You can activate the menu by holding down the mouse for about one second. This provides a more accessible approach to popping up a Secondary Menu. This technique is used in the Macintosh Dock. Clicking and holding down on an application in the dock will reveal the Secondary Menu without requiring a right-click activation.
Keep in mind that all of the other Contextual Tools presented in this chapter have a limitation on the number of items they can operate on. Always-Visible Tools, Hover-Reveal Tools, Toggle-Reveal Tools, and Multi-Level Tools all operate on a single item at a time (even Toggle-Reveal Tools just shows a tool per item). Secondary Menus are different. They can be combined with a selection model (as described in Chapter 3) to perform actions on selected set of items.