how to increase thickness of slider conrol in mfc
                
                A: 
                
                
              MoveWindow() can be used for any MFC control. Try this:
CRect rc;
slider.GetWindowRect(rc);    // Get the slider rectangle in absolute corrdinates
rc.InflateRect(30, 30);      // Do whatever you want with your rectangle;
ScreenToClient (rc);         // Convert to dialogs's coordinates
slider.MoveWindow(rc);       // Move it!
Update:
For further customization you have to make an owner-drawn CListCtrl. You may take this article as a good start for that
                  mmonem
                   2010-09-19 14:38:48
                
              @mmonem movewinow will increase size horizontally for scrollbar but how can we increase height of bar i.e. i am trying to increase thickness of slider bar
                  
                   2010-09-20 10:30:36
                Check the updated answer
                  mmonem
                   2010-09-20 12:54:32