Change settings when playing an action
By default, actions are completed using the values specified when they were originally recorded. If you want to change the settings for a command within an action, you can insert a modal control. A modal control pauses an action so that you can specify values in a dialog box or use a modal tool. (A modal tool requires pressing Enter or Return to apply its effect—once you press Enter or Return, the action resumes its tasks.)
A modal control is indicated
by a dialog box icon 
to
the left of a command, action, or set in the Actions palette. A
red dialog box icon 
indicates
an action or set in which some, but not all, commands are modal.
You can’t set a modal control in Button mode.
Do one of the following:-
To enable a modal control for a command within an action, click the box to the left of the command name. Click again to disable the modal control.
-
To enable or disable modal controls for all commands in an action, click the box to the left of the action name.
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To enable or disable modal controls for all actions in a set, click the box to the left of the set name.