Component Activation (CDE)

Pressing the SELECT button activates a push button.

When a push button has focus, pressing Select or Spacebar activates it.

When an activatable menu entry has the focus, pressing Select, Spacebar, Enter, or Return activates the entry.

When the SELECT button is pressed over a push button, change the appearance of the push button to indicate that releasing the SELECT button will activate the push button. If, while the SELECT button is pressed, the pointer is moved outside of the push button, restore the visual state. If, while the SELECT button is still pressed, move the pointer back inside of the push button and change the visual state again to indicate the pending activation. If the SELECT button is pressed and released within a push button, activate the button, regardless of whether the pointer has moved out of the push button while it was pressed.

If a selectable element of a collection is activatable, clicking the SELECT button, pressing Select, or pressing Spacebar (except in text) selects it. Double-clicking the SELECT button selects and activates it.

The time allowed to detect a double-click (**doubleClickTime: 500) should be no less than 500 milliseconds.

If your application uses accelerators (shortcut keys), the component with the accelerator should display the accelerator key or key combination following the label of the component.

If a button with an accelerator is within a primary or secondary window, or within a pull-down menu from its menu bar, make it activatable whenever the input focus is in the window or the menu-bar system. If a button with an accelerator is within a pop-up menu, make it activatable whenever the focus is in the pop-up menu or the component with the pop-up menu.

An accelerator must be activatable from the window or component associated with the accelerator.

If your application uses mnemonics, the label for the component with the mnemonic should contain the character that is its mnemonic. If the label does not naturally contain the character, place the mnemonic in parentheses following the label.

Mnemonic characters must be chosen for ease-of-location within the text of a label. Wherever possible, use the first character of the label. If that is not possible, use the last character of the label or, if there is more than one word, the first character of the second word. After that, go through the label from the second character on until a unique mnemonic is found.

Make all mnemonics case insensitive for activation.

When the location cursor is within a menu or a menu bar, pressing the mnemonic key of a component within that menu or menu bar moves the location cursor to the component and activates it. If a mnemonic is used for an option button or for a cascading button in a menu bar, pressing Alt and the mnemonic anywhere in the window or its menus moves the cursor to the component with that mnemonic and activates it.

When the user activates a tear-off choice, tear off the menu that contains the choice.

When a menu with a tear-off choice is posted, pressing the TRANSFER button in the tear-off choice starts a tear-off action. As long as the TRANSFER button is held, a representation of the menu should follow the movement of the pointer. Releasing the TRANSFER button ends the tear-off action by unposting the menu system, creating a new window at the current pointer location that contains the contents of the menu, and giving focus to the new window in explicit pointer mode.

When the user presses Help on a component. invoke any context-sensitive help for the component or its nearest ancestor with context-sensitive help available.

Provide context-sensitive help at all locations.

Never use a "Help not available" message.

If your application uses default push buttons in a window, highlight the current default push button. When the focus is on a push button, make its action the default action and highlight the push button. If the default action in a window varies, some push button must always have default highlighting, except when there is no current default action.

When focus is in a window with a default action and an activatable menu does not have the focus, pressing Enter or Ctrl Return invokes the default action. If focus is in a component other than multiline text or an activated menu, Return also invokes the default action. These actions should have no other effect on the component with the focus, unless the default action has some effect on that component.

Except in the middle of a button motion operation, make pressing Cancel anywhere in a dialog box equivalent to activating the Cancel push button in the dialog box.

If your application supports expert activation, expert actions should exist only as shortcuts to application features that are available through another mechanism.

Expert activation, using mouse double-clicking on buttons, provides a convenient way for experienced users to perform certain tasks quickly. However, new users and keyboard-only users need to be able to perform the same tasks.

When the focus is on a button used for expert activation, no default action should be available, unless the default and expert actions are the same.

If a component with an expert action is selectable, activating the expert action first selects the component and then performs the expert action.

If your application supports activation preview when the user presses the SELECT button, remove the previewing information when the user releases the SELECT button. Activation preview presents the user with additional information that describes the effect of activating a button. This information cannot interfere with the normal operation of the application.

Pressing the Cancel key stops current interaction in the following contexts: