Other labels
5. Window Decorations
Panel Plugins
WM title bar and window borders or Client Side Decorations (CSD)
5. Panel Menu / Widget
Panel Plugins
The menu / widget that opens up when you left click a panel plugin
Whisker Menu
Panel Plugins / xfce4-whiskermenu-plugin
The searchable applications menu that opens when clicking the button/label in the panel
Prioritized