At any given moment, a given scroll bar will have a
single 'selection' that is considered to be its
value, which is constrained to be within the range of
values the scroll bar represents (that is, between its
minimum and maximum values).
Typically, scroll bars will be made up of five areas:
On some platforms, the size of the scroll bar's thumb can be
varied relative to the magnitude of the range of values it
represents (that is, relative to the difference between its
maximum and minimum values). Typically, this is used to
indicate some proportional value such as the ratio of the
visible area of a document to the total amount of space that
it would take to display it. SWT supports setting the thumb
size even if the underlying platform does not, but in this
case the appearance of the scroll bar will not change.
Scroll bars are created by specifying either H_SCROLL,
V_SCROLL or both when creating a Scrollable.
They are accessed from the Scrollable using
getHorizontalBar and getVerticalBar.
Note: Scroll bars are not Controls. On some platforms, scroll bars
that appear as part of some standard controls such as a text or list
have no operating system resources and are not children of the control.
For this reason, scroll bars are treated specially. To create a control
that looks like a scroll bar but has operating system resources, use
Note: Only one of the styles HORIZONTAL and VERTICAL may be specified.
IMPORTANT: This class is not intended to be subclassed.