After I upgraded Ubuntu MATE from 16.04 to 18.04, I noticed a really annoying behavior. Clicking in the empty area of a scrollbar (between the handle showing where your current position is and the up or down arrow) used to scroll up or down a page at a time. After the 18.04 upgrade, this behavior changed, and now it moves the handle directly to the position where you clicked. Some people like this, some people don’t. I don’t. Unfortunately, they didn’t decide to make this a configurable option in the graphical settings for some strange reason.

It turns out that this is actually a GTK 3 behavior — it’s caused because MATE recently changed to use GTK 3. Luckily, it’s an easy fix:

Go into the directory of the theme you are currently using. So for my current configuration, I went into this directory:

/usr/share/themes/Ambiant-MATE/gtk-3.0

Edit the “settings.ini” file. Add the following line to the bottom of it:

gtk-primary-button-warps-slider = false

Log out and back in, and you’re done.

After upgrading my machines from Ubuntu MATE 16.04 to 18.04, I noticed that something was subtly wrong with my top menu/panel: the network notification icon was missing. Something about the 16.04 to 18.04 upgrade process broke it. It happened on both of the machines I upgraded, so I don’t think it was a random thing that only I was experiencing.

Note: my fix for this will reset your panel layouts, so take a screenshot and/or save any info about the layout of your panels before following the steps below so you will have a reference for restoring it back the way you want it afterward.

To start out, I will share some background info:┬áif you are used to the default menu layout of the top panel with the Applications, Places, and System menus, they decided to change this in 18.04. That layout is called “Traditional”, and Ubuntu MATE 18.04 now defaults to a new layout called “Familiar”. I personally don’t like the Familiar layout because it doesn’t have the Places menu, but I guess enough people liked it that they wanted to make it the default.

Anyway, the fix for this is to reset your panel to one of the default configurations, which will add everything back properly. But like I said in bold above, it will also erase any customizations you have done. Here’s the fix:

  1. Open up MATE Tweak. In the Traditional layout, it’s in the System -> Preferences -> Look and Feel menu.
  2. In MATE Tweak, click on the Panel category.
  3. In the top dropdown menu, choose the layout you want. To match Ubuntu 16.04’s default, choose Traditional. To match Ubuntu 18.04’s default, choose Familiar.
  4. Confirm that you want to change the layout by clicking OK.
  5. All done! Your network notification icon should be restored, and now you can reapply any of your customizations to the panel.

Another way to fix it is to right-click on the panel and choose Reset Panel, but I think the method I described above is better because it lets you pick which layout you want to start from.

I recently upgraded a couple of my machines from Ubuntu MATE 16.04 to 18.04. On both of them, I noticed that after the upgrade, the login window did not look correct. There was no background image. It didn’t look like a fresh 18.04 install. Plus, any changes I did in the Administration -> Login Window program didn’t take effect. I did some digging, and figured out what was going on.

Sometime between 16.04 and 18.04 (it appears that this happened starting in 17.10), Ubuntu MATE decided to stop using lightdm-gtk-greeter, and instead switched to using slick-greeter. It seems to be that on update installs, lightdm-gtk-greeter is not being removed, so it’s defaulting to using it rather than slick-greeter.

I was able to solve this very easily by running the following command:

sudo apt purge lightdm-gtk-greeter

After that, I logged out, and Ubuntu MATE’s correct login screen appeared. It’s as simple as that!