Can you save a mask?
How to dock a pallet on the bottom of the workspace?
Is there a way to organize the brush pallet the way you want?
About organising your ZBrush UI (palletes etc) in ZBrush you can do this:
Preferences > CustomUI > Enable Customization
You can then move palletes, icons or buttons with ctrl & drag or even erase something by ctrl & drag and droping it in the canvas.
You can also check this video for more about ZB Interface:
http://www.vimeo.com/2477345
About saving masks, personally don’t know yet if this exists but anyways i use polygroups instead and work them as isolated parts.
You can do this is selecting the areas you want to work seperately with the lasso (with Ctrl+Shift) and choose Tools > Polygroups > Group Visible
Good info but I want to dock a pallet on the bottom shelf do you know how to do that? Drag and dropping it dose not work for the bottom self??? 
small_orange_diamond
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you can save a mask by saving it as a alpha, you must have uv’s for this to work.
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you can’t, only buttons
3.you would need to make a custom menu