i think that muse is really, really, REALLY, wasting space. you have actually only three ways for arranging your windows:
1. the pianoroll (or whatever you're working with) full-screen, the main window hidden behind
2. the main-window full-screen, and the pianoroll aligned that it covers your whole screen width, but resized vertically so that you still see the arranger and muse's main window's menus etc.
3. a pianoroll and a drum-roll half-screen each, so that you can see and manipulate melody and drums at the same time

#1 has the great disadvantage that you only can edit notes. you cannot rearrange parts, you cannot quickly mute some part

#2 and #3 waste lots of space

for example, only the toolbars i sometimes need (and i think, if possible (and it would be possible if done properly), all stuff which _may_ be sometimes needed must be accessible. not only the often-needed stuff) alone take two toolbar-rows. plus one row for the menu, which is almost completely redundant. plus, of course, the window decoration / the "title bar" you can grab and move around.

all this could be solved as follows:

remove the menu bar:

clean up toolbars:

this boils down to the following: move all menus to the main window and only display the active window's toolbars, remove redundant toolbars

the "side bar" which displays track information can be removed from pianoroll and drumroll, as that's only redundant code (can be kept, as it's hideable, but it unnecessary.)

the arranger has to be vertically resizable and also hidable. beneath the arranger will be the "window area".

the windows are children of the main window. that is, they are "within" the main win. maxizing them won't make them cover the full screen, but the full "window area" below the arranger.

the main win could offer window-control-functions like "create 2x2 grid layout" or "create 1x4 layout"

this "new" (let's call it "mine", and the current "yours") layout has the following advantages:
i've tried using muse as i used my old, beloved cakewalk ;) . it didn't work, because i wasn't able to stack as many windows with muse on a 1024x768 screen as with cakewalk on a 800x600 (!) screen. muse needs bigger resolutions and still offers less space!

please let me know what you think about this ideas.

of course, it will require some (minor, however) changes in muse. but i think it will really simplify using it (at least if you don't have huge screens)