In the correct Java implementation (Sun JDK, Netscape 4.06 and later), the slider occupies all of the scrollbar because value=0 and visible=50, so the right side of the slider is at 50.

In a buggy browser such as Microsoft Explorer 3.0-5.0 (java.version <= 1.1) and Netscape 2.0-4.05, the slider occupies only the left half of the scrollbar, because the maximum parameter is the maximum rightmost position of the left side of the slider.

Scrollbug.java

Workaround: 
vendor = System.getProperty("java.vendor");
ver = System.getProperty("java.version");
scrollbug = (vendor.equals("Microsoft Corp.")
                && (ver.startsWith("1.0") || ver.equals("1.1"))) 
            || (vendor.equals("Netscape Communications Corporation")
                && (ver.startsWith("1.0") || ver.equals("1.1.2"))); 
maximum = scrollbug? maxright - visible : maxright;
scrollbar.setValues(value, visible, minimum, maximum);