When starting Emacs without tool-bar and without menu-bar the windows shrinks automatically to the size of one (text) line.
To reproduce, run current Unity desktop (5.4.0-0ubuntu2) and start Emacs with the following command line:
emacs23 -Q --execute "(progn (tool-bar-mode 0)(menu-bar-mode 0))"
Note that both toolbar and menubar have to be disabled to see the shrinking behavior.
FWIW, here's a video that illustrates the behavior: http://www.youtube.com/watch?v=_oKQjP8x_Os
ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: emacs23 23.3+1-1ubuntu8
ProcVersionSignature: Ubuntu 3.2.0-17.27-generic 3.2.6
Uname: Linux 3.2.0-17-generic x86_64
ApportVersion: 1.93-0ubuntu2
Architecture: amd64
Date: Mon Feb 27 07:44:46 2012
ExecutablePath: /usr/bin/emacs23-x
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120201.2)
ProcEnviron:
TERM=xterm
SHELL=/bin/bash
PATH=(custom, user)
LANG=de_DE.UTF-8
SourcePackage: emacs23
UpgradeStatus: Upgraded to precise on 2012-02-10 (16 days ago)
One more observation: Using emacs-gtk (instead of emacs-x) it seems that enabling/disabling menu-bar-mode has no effect and the behavior is reproducible by just turning off tool-bar-mode.