## Declaring a context id

The setHelp method in org.eclipse.ui.help.IWorkbenchHelpSystem is used to associate a context id with a `Control`, `IAction`, `Menu`, or `MenuItem`. The context id should be fully qualified with the plug-in id. For example, the following snippet associates the id "com.example.helpexample.panic_button" with a button in the application.

    PlatformUI.getWorkbench().getHelpSystem().setHelp(myButton, com.example.helpexample.panic_button);

The following UI controls cannot have context ids (and therefore cannot have context-sensitive help):

- Toolbar buttons (ToolItem)
- CTabItem
- TabItem
- TableColumn
- TableItem
- TableTreeItem
- TreeItem

Widgets that do not get focus should not be assigned context ids, since they will never trigger a context-sensitive help.