Window List panel applet behaves unusually in Antergos Mate 1.14.0.
This behaviour is difficult to note when the panel is expanded (the default setting). It is immediately noticeable when the panel is not expanded towards the left-right screen edges.
Normally, even if the panel is not expanded, the Window List applet reserves an empty space on the panel. The first opened window occupies this space. When other windows are opened, their titles are added to the right in the applet.
An example of not expanded panel with empty Window List applet. Empty space is reserrved, normal behaviour, Antergos Mate 1.12.1:
An example of not expanded panel with one opened Add to Panel window. Empty space in Window List applet is taken by opened window, normal behaviour, Antergos Mate 1.12.1:
In Antergos Mate 1.14.0 the empty Window List applet (no windows are opened) is shrinked to 0-width. The applet is still present in the panel but is not visible (unusual behaviour):
When a window is opened, the applet becomes visible and holds the window’s title; other opened windows titles are added to the right in the applet (normal behaviour, Antergos Mate 1.14.0):
Window List applet’s shrinking to 0-width without opened window(s) in not expanded panel is not present in other distros having Mate 1.14. The applet correctly reserves the empty space.