Returns the background color of the line at the given index.
Returns null if a LineBackgroundListener has been set or if no background
color has been specified for the line. Should not be called if a
LineBackgroundListener has been set since the listener maintains the
line background colors.
@param index the index of the line
@return the background color of the line at the given index.
@exception SWTException <ul>
<li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
<li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
</ul>
@exception IllegalArgumentException <ul>
<li>ERROR_INVALID_ARGUMENT when the index is invalid</li>
</ul>
Returns the background color of the line at the given index. Returns null if a LineBackgroundListener has been set or if no background color has been specified for the line. Should not be called if a LineBackgroundListener has been set since the listener maintains the line background colors.
@param index the index of the line @return the background color of the line at the given index.
@exception SWTException <ul> <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> </ul> @exception IllegalArgumentException <ul> <li>ERROR_INVALID_ARGUMENT when the index is invalid</li> </ul>