absolute positioning according to preferred size of panels,
scrolling one message per unit
rendered messages are cached
<?xml version="1.0"?>
<!DOCTYPE DOCKABLES SYSTEM "dockables.dtd">
<DOCKABLES>
<DOCKABLE NAME="Isabelle_output">
new isabelle.jedit.OutputDockable(view, position);
</DOCKABLE>
<DOCKABLE NAME="Isabelle_state">
new isabelle.jedit.StateViewDockable(view, position);
</DOCKABLE>
<DOCKABLE NAME="Isabelle_scroller">
new isabelle.jedit.LazyScroller(view, position);
</DOCKABLE>
</DOCKABLES>