question: private void handleMouseMove ( final Event e ) { final int x = e . x , y = e . y ; final Image img = orientation == SWT . HORIZONTAL ? slider : vSlider ; upperHover = x >= coordUpper . x && x <= coordUpper . x + img . getBounds ( ) . width && y >= coordUpper . y && y <= coordUpper . y + img . getBounds ( ) . height ; lowerHover = x >= coordLower . x && x <= coordLower . x + img . getBounds ( ) . width && y >= coordLower . y && y <= coordLower . y + img . getBounds ( ) . height ; if ( dragInProgress ) { if ( orientation == SWT . HORIZONTAL ) { final int mouseValue = ( int ) ( ( x - 9f ) / computePixelSizeForHorizonalSlider ( ) ) + minimum ; if ( lastSelected == SELECTED_KNOB . UPPER ) { upperValue = ( int ) ( Math . ceil ( mouseValue / increment ) * increment ) - increment ; checkUpperValue ( ) ; } else { lowerValue = ( int ) ( Math . ceil ( mouseValue / increment ) * increment ) - increment ; checkLowerValue ( ) ; } } else { final int mouseValue = ( int ) ( ( y - 9f ) / computePixelSizeForVerticalSlider ( ) ) + minimum ; if ( lastSelected == SELECTED_KNOB . UPPER ) { upperValue = ( int ) ( Math . ceil ( mouseValue / increment ) * increment ) - increment ; checkUpperValue ( ) ; } else { lowerValue = ( int ) ( Math . ceil ( mouseValue / increment ) * increment ) - increment ; checkLowerValue ( ) ; } } } redraw ( ) ; }
target:  Code executed when the mouse pointer is moving