The following is a list of known issues with MATE on Slackware:

Sun Mar 24 02:47:56 UTC 2013
If you run into strange panel issues, or missing icons, or theme problems,
please consider backing up or clearing out some of the hidden directories in
your $HOME, like $HOME/.config and $HOME/.cache and $HOME/.local.  If you
switch back and forth between different desktop environments, sometimes those
settings can get polluted.

Sun Mar 24 02:44:53 UTC 2013
A couple of users have reported Caja (the file manager) crashing with an error
message telling the user to run Caja with the --sync option.  Please let me
know if you run into this.  Before doing so, however, please consider backing
up or clearing out some of the hidden directories in your $HOME, like
$HOME/.config and $HOME/.cache.  If you switch back and forth between
different desktop environments, sometimes those settings can get polluted.

Fri Mar 22 16:45:28 UTC 2013
Mate-screensaver in /testing doesn't seem to work -- at least, the locking
feature does not seem to work in my testing.  I tried it with xscreensaver
disabled and also uninstalled but it never kicked in.  More testing is
necessary.

Fri Mar 22 16:44:59 UTC 2013
Help menus and help buttons do not work -- this is a known issue per a MATE
upstream developer and scheduled to be fixed at some point but not in the next
release (1.6).

Fri Mar 22 16:43:36 UTC 2013
Working to determine whether mate-polkit is necessary.  According to upstream,
it is, although it results in duplicative polkit actions when a USB stick is
inserted, for example.  Disabling polkit-gnome in the "Startup Applications"
is a workaround until more testing is done.