In kde 3.4.1 (started happening since kde 3.3.2) every time a maximized window is unmaximized on screen appears a little dialog (i'd say a QMessageBox::information if you know Qt) with caption "Notification -" (the window is too tiny to read the rest of the caption) and a message (above the OK button) saying: "Unmaximize" Reproducible: Always Steps to Reproduce: 1. 2. 3. Portage 2.0.51.19 (default-linux/amd64/2005.0, gcc-3.4.3, glibc-2.3.4.20041102-r1, 2.6.11-gentoo-r11 x86_64) ================================================================= System uname: 2.6.11-gentoo-r11 x86_64 AMD Athlon(tm) 64 Processor 3000+ Gentoo Base System version 1.6.12 Python: dev-lang/python-2.3.5 [2.3.5 (#1, Jun 11 2005, 19:35:33)] distcc 2.18.3 x86_64-pc-linux-gnu (protocols 1 and 2) (default port 3632) [disabled] ccache version 2.3 [enabled] dev-lang/python: 2.3.5 sys-apps/sandbox: [Not Present] sys-devel/autoconf: 2.59-r6, 2.13 sys-devel/automake: 1.9.5, 1.5, 1.8.5-r3, 1.6.3, 1.7.9-r1, 1.4_p6 sys-devel/binutils: 2.15.92.0.2-r10 sys-devel/libtool: 1.5.16 virtual/os-headers: 2.6.8.1-r4 ACCEPT_KEYWORDS="amd64" AUTOCLEAN="yes" CFLAGS="-march=k8 -O2 -pipe -fweb -ftracers" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/2/share/config /usr/kde/3.3/env /usr/kde/3.3/share/config /usr/kde/3.3/shutdown /usr/kde/3.4/env /usr/kde/3.4/share/config /usr/kde/3.4/shutdown /usr/kde/3/share/config /usr/lib/X11/xkb /usr/share/config /usr/share/texmf/dvipdfm/config/ /usr/share/texmf/dvips/config/ /usr/share/texmf/tex/generic/config/ /usr/share/texmf/tex/platex/config/ /usr/share/texmf/xdvi/ /var/qmail/control" CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d" CXXFLAGS="-march=k8 -O2 -pipe -fweb -ftracers" DISTDIR="/usr/portage/distfiles" FEATURES="autoaddcvs autoconfig candy ccache distlocks sandbox sfperms strict" GENTOO_MIRRORS="http://distfiles.gentoo.org http://distro.ibiblio.org/pub/Linux/distributions/gentoo" LINGUAS="en it" MAKEOPTS="-j2" PKGDIR="/usr/portage/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" SYNC="rsync://rsync.gentoo.org/gentoo-portage" USE="amd64 X a52 aac acpi alsa arts avi berkdb bitmap-fonts bluetooth cdr crypt cscope cups curl dvd dvdr encode esd fam flac font-server foomaticdb fortran gdbm gif gpm gtk gtk2 imagemagick imlib jp2 jpeg kde libwww lzw lzw-tiff mad matroska mbox mikmod motif mp3 mpeg ncurses nls ogg oggvorbis opengl oss pam pcre perl png python qt readline samba sdl spell sqlite ssl tcpd tetex theora tiff truetype truetype-fonts type1-fonts usb userlocales vorbis xine xml2 xmms xpm xprint xrandr xscreensaver xv xvid zlib linguas_en linguas_it userland_GNU kernel_linux elibc_glibc" Unset: ASFLAGS, CBUILD, CTARGET, LANG, LC_ALL, LDFLAGS, PORTDIR_OVERLAY
Just FYI, -ftracers is not a valid C[XX]FLAGS, see man gcc.
Go to Control Center, Sound & Multimedia, System Notification, select "The KDE Window Manager" as event source, and select the event "A window loses maximisation"; click on More Options and disable "Show a message in a pop-up window" checkbox. That should do.
