Install any desktop on opensuse 13.2

Hello community
Have been doing some research and I have installed , with success, mate desktop with lightdm, fully working 32 and 64 bits drivers (I needed openGL 32bits for games on steam such as Dota2, TF2, CS:GO, …) So, what I want to test is removing gnome desktop to stay iceWM, MATE and TWM ( I guess is what I have now ).
/usr/share/xsessions dir:

share/xsessions% ls
gnome.desktop  icewm.desktop  mate.desktop  twm.desktop

and this is my config of windowmanager:

/etc/sysconfig% cat windowmanager 
## Type:    string
## Default:
## Path: Desktop
## Description: default mouse cursor theme
#
# Name of mouse cursor theme for X11. Possible themes can be found
# in /usr/share/icons/
#
X_MOUSE_CURSOR="DMZ"
## Path:    Desktop/Window manager
## Description:    
## Type:    string(gnome,kde4,kde,lxde,xfce,twm,icewm)
## Default:    kde4
## Config:      profiles,kde,susewm
#
# Here you can set the default window manager (kde, fvwm, ...)
# changes here require at least a re-login
DEFAULT_WM="mate-session"

## Type:    yesno
## Default:    yes
#
# install the SuSE extension for new users
# (theme and additional functions)
#
INSTALL_DESKTOP_EXTENSIONS="yes"
/etc/sysconfig%

and my displaymanger config:

/etc/sysconfig% cat displaymanager 
## Path:        Desktop/Display manager
## Type:        string(Xorg)
## Default:     "Xorg"
#
DISPLAYMANAGER_XSERVER="Xorg"
## Path:    Desktop/Display manager
## Description:    settings to generate a proper displaymanager config
## Type:    string(kdm,xdm,gdm,wdm,entrance,console,lightdm,sddm)
## Default:    ""
#
# Here you can set the default Display manager (kdm/xdm/gdm/wdm/entrance/console).
# all changes in this file require a restart of the displaymanager
#
DISPLAYMANAGER="lightdm"

## Type:    yesno
## Default:    no
#
# Allow remote access (XDMCP) to your display manager (xdm/kdm/gdm). Please note
# that a modified kdm or xdm configuration, e.g. by KDE control center
# will not be changed. For gdm, values will be updated after change.
# XDMCP service should run only on trusted networks and you have to disable
# firewall for interfaces, where you want to provide this service.
#
DISPLAYMANAGER_REMOTE_ACCESS="yes"

## Type:    yesno
## Default:    no
#
# Allow remote access of the user root to your display manager. Note
# that root can never login if DISPLAYMANAGER_SHUTDOWN is "auto" and
# System/Security/Permissions/PERMISSION_SECURITY is "paranoid"
#
DISPLAYMANAGER_ROOT_LOGIN_REMOTE="yes"

## Type:    yesno
## Default:    yes
#
# Let the displaymanager start a local Xserver.
# Set to "no" for remote-access only.
# Set to "no" on architectures without any Xserver (e.g. s390/s390x).
#
DISPLAYMANAGER_STARTS_XSERVER="yes"

## Type:        yesno
## Default:     no
#
# TCP port 6000 of Xserver. When set to "no" (default) Xserver is
# started with "-nolisten tcp". Only set this to "yes" if you really
# need to. Remote X service should run only on trusted networks and
# you have to disable firewall for interfaces, where you want to
# provide this service. Use ssh X11 port forwarding whenever possible.
#
DISPLAYMANAGER_XSERVER_TCP_PORT_6000_OPEN="no"

## Type:    string
## Default:
#
# Define the user whom should get logged in without request. If string
# is empty, display standard login dialog.
#
DISPLAYMANAGER_AUTOLOGIN=""

## Type:        yesno
## Default:     no
#
# Allow all users to login without password, but ask for the user, if
# DISPLAYMANAGER_AUTOLOGIN is empty.
#
DISPLAYMANAGER_PASSWORD_LESS_LOGIN="no"

## Type:        yesno
## Default:     no
#
# Display a combobox for Active Directory domains.
#
DISPLAYMANAGER_AD_INTEGRATION="no"

## Type:    list(root,all,none,auto)
## Default: auto
#
# Determine who will be able to shutdown or reboot the system in kdm.  Valid
# values are: "root" (only root can shutdown), "all" (everybody can shutdown),
# "none" (nobody can shutdown from displaymanager), "auto" (follow
# System/Security/Permissions/PERMISSION_SECURITY to decide: "easy local" is
# equal to "all", everything else is equal to "root").  gdm respects the
# PolicyKit settings for ConsoleKit. Shutdown configuration can be done via
# the polkit-default-privs mechanism.
#
DISPLAYMANAGER_SHUTDOWN="auto"

So, it is safe to uninstall any gnome package like: gnome-core or gnome-session ? Can I use any other software like: gnome-disk-utility on mate? I find some software with “gnome” on it saying is for gnome, but can I run that on other desktop like KDE? I have amarok and it runs here very well on mate. But the disks utility (gnome-disk-utility) have not the same “window layout” like the other software for mate.
I need to clear this ideas in order to make a move to remove gnome, and maybe installing KDE just for fun (but MATE for work stuff).
Oh almost forgot. I have this issue when I open some software that was “maximized” before closing:
http://i.imgur.com/mnsVqS2.png

And now I just drag the tab to the middle of the screen or just click “restore” and maximize then it backs to normal:
http://i.imgur.com/K2BeS9g.png

But is kind of boring doing always this.
This is gnome-disk-utility (i did now on a VM) check the layout:
http://i.imgur.com/itBOfct.png

you’re mixing a lot of the basics, gnome applications are gtk3 and mate is gtk2, to get gnome apps looking like mate you might need a mate theme that has gtk3 support.
In principle you do not need gnome for mate, you might find some gnome packages useful, but be careful with dependencies by removing one gnome package you might brake something, you can safely remove evince or nautilus if you have them, but do not remove everything with gnome in it’s name.
seriously using mate for work and kde for fun is a bad idea, I’d say use kde for work and mate for fun, why because kde is more mature and stable then mate, it has more applications and more users, kde has more developers and a lot of third party applications will support kde almost none will support mate.
ps. I’m not hating on mate I use it and like it.

It is difficult to uninstall a desktop since there are so many dependencies. Better not to have installed it in the first place. But really why uninstall?? It just takes up a bit of disk space.