Sets the script progress bar to a value of v (in percent full scale). Setting v to a negative value hides the script progress bar. If the script bar is not visible when calling this function, the script bar is made visible as well.
Further, a button to abort the script is displayed to the right of the script bar. Please note that abortion of a script is not possible if the script displays a modal window (i.e. a window which does not allow to shift the focus of it to another one). Modal windows are typically message dialogs.
The status text panels and the main status bar are not changed at all (use ShowStatus for this purpose).