Dimming is a visual indication that some command or activity is not possible at that moment.
Dimming is an important feature especially in touch usage and notably supports user action with touch UI. Tactile feedback is not given when user touches a dimmed area except if pop-up without softkeys is closed.
The entire screen is dimmed in the background when the Options and power menu, floating toolbars, notes, soft notifications, settings editors or queries are displayed.
In some situations, it may be necessary to dim unavailable controls. This is done on the component level so that a control has a normal and a dimmed state, for example, toolbar button.
Dimming indicates that the control is temporarily not available. For example, function is not possible for the focused item, but for the other items in the view. Dimming should not be used if the user never sees the control in active state within that view. In this case unavailable control is to be hidden.