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

Sat Apr  9 02:20:05 UTC 2016
Help menus and help buttons are now enabled but they will not be usable
unless you have yelp (this requires webkit2gtk not provided here, but
available in SBo). For those interested to build yelp, you may
find the SlackBuild in testing/yelp.

Mon Jun 10 03:09:28 UTC 2013 (FIXED)
If you are encountering problems with Caja (MATE's file manager) opening
directories when clicking on files in certain programs like Dropbox, Skype,
and others, please execute the following steps to fix it:

As your regular user, back up the following file:
$HOME/.local/share/applications/defaults.list and then enter the next two
commands in a terminal to set the default handler:

xdg-mime default caja-folder-handler.desktop inode/directory
xdg-mime default caja-folder-handler.desktop application/x-directory

You should be all set.  Thanks to Totoro-kun and T3slider for reporting and
discussing this in the LQ forums and also thanks to Giorgos Keramidas for
creating the initial patch.  Here is a link to the LQ thread which also has
a link to Giorgos's blog with the patch:

http://www.linuxquestions.org/questions/showthread.php?p=4968614

UPDATE: Mon Mar 13 01:27:06 UTC 2017
mate-desktop has been updated to provide default application for some categories.
This will only work with new user. Existing user will not be affected and manual
intervention will still be needed.

Wed Mar 27 04:23:24 UTC 2013
If you have dual monitor with NVidia card and set it up to use both monitors
as separate, you might encounter some freeze lockup.  A temporary workaround
is to change it into TwinView in your xorg.conf

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. You can also try to remove/rename your
.gtkrc-2.0 if it does exists on your home directory.

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.