Buttons are intended to perform some actions available in a form. To use a button, click it or activate it using Tab or Shift + Tab and then press Enter.
One of the form buttons can be the default one, and you can use it not only by clicking but also by pressing Ctrl + Enter.
Fig. 55. A form button
Some buttons have keyboard shortcuts that duplicate their functions. You do not have to select or activate a button prior to using a keyboard shortcut.
Some buttons have "pressed" and "released" states. They indicate that some application mode is enabled or disabled.
If the action associated with a button is not available, the button appears shaded.
Fig. 56. The button is not available