The Windows 10 system tray has two sections: a section with icons that are always visible, and a section with icons that you only see when you click the extended system tray button. If an icon is hidden in the extended system tray, you can simply drag it from the extended tray to the standard tray to reveal it.
Show or hide icons in the taskbar, system tray, or desktop in Windows 10
Here's how to show hidden icons in the Windows 10 system tray:
Click the ^ icon to the left of the system tray icons to open the expanded system tray.
Click and hold an icon in the expanded system tray.
