in the disk space analyzer Baobab, the graphical representation on the right part occupies very much space.
How can I disable it?
This is not a proper answer to your question, but if you're only interested in your disk usage without a graphical representation, you could try gt5.
It works in the terminal, and shows you the % usage of directories. Also I like that every time you run it, it tells you which directories have increased or decreased in size. It's nice to keep track when you're trying to do some hard drive clean-up.
And to run it:
The results open in a terminal browser inside the terminal but you can still use your mouse to browse between directories.