The scrolling direction of a Ticker is
language and localization dependant. If the Ticker string
consists of only whitespace, it is not shown.
If setString() is called while the Ticker is
visible, the Ticker restarts with the new string.
If a Displayable has an active Ticker when
a popup is activated, the Ticker is displayed dimmed
and active in the background.
The height of a Ticker may vary according to the
phone language selected by the user. Each time the Ticker string
is updated, the Ticker height is adjusted, if necessary,
to accommodate the text to be displayed.