Yes, this is a know bug.
Java applets are problematic in some ways: for example the scanner applet has problems with some scanners and it is based on a library with has not been maintained for years. People reports problems, and we are not sure if remove from OpenKM because we can't fix them. I have looked for a replacement for this library but all the candidates are commercial implementations which cost several hundred of euros. If we use this library, this applet need to be removed from the Community version of OpenKM due to license restrictions. We are evaluation for the Professional version but we have no decided anything. Sadly, develop a Windows client application seems the most convenient way of doing it.