It'd be nice if the tabs for a track (ie samples, instruments, patterns, etc.) could be floated and docked anywhere you wanted, a bit like in most modern IDEs. So, for example, you could grab the "general" page, and dock it below the pattern editor, to mix you channels globally while still watching them. Or you could stick the instrument editor beneath the pattern editor and mess about with an instrument's volume envelope or what have you. It'd make the user interface a lot more flexible - you could even throw the pattern editor onto one monitor and everything else onto another.
Closing this one.
See topic: http://forum.openmpt.org/index.php?topic=828.0