MS IE : applets need a first click to be 'activated'. Solution : Use Firefox instead .
MS IE 6 stalls. Solution : Use Firefox instead .
Older versions of MS IE 5.0 with the MS JVM don't handle popup menu choices of the source code pane correctly. Solution : Sun's JDK 6you only need SE, not the extras .
Macintosh + Firefox : Lessonviewer won't show (part of) its contents. Not solved yet, trying another browser might work.
MS IE 4.x is not supported, its Java implementation is inadequate.
Opera : Textfield won't get focus, even when you click it. Solution : Click next to the textfield.
Opera : Lesson viewer doesn't appear or 'can't be found' . Reload by going to previous page : Alt-left arrow, and going back : Alt-right arrow.
Opera 7, JVM 1.4.0 : Not stable.
General : Lesson viewer shows gibberish. Close browser and reopen.