Do not show volumes as safely removable for system drive installed in external USB enclosure

I have up-to-date Arch Linux with KDE Plasma installed on SSD inside external USB enclosure. The problem is that the volumes of this drive are displayed in system tray with options to safely remove them. This seems pretty useless, so is there any elegant way to make them not to show there? If this matters, the drive is Samsung 840 Pro and the enclosure is one of those based on ASM1351 chipset. The drive in enclosure is handled by uas driver in the system. cat /sys/block/sdb/removable returns 0 (sdb is the subject drive). The volumes, which are displayed in the tray are mounted at / and /home. The system is booted in UEFI mode, and what's interesting is that the ESP (EFI System Partition), which is mounted at /boot, is not shown in system tray. I switched to UEFI boot only recently, and noticed, that before the switch, the /boot was shown in system tray among the other volumes. Not sure, however, if this info is helpful. None of these volumes are shown in system tray when the drive is connected to the mobo using regular internal SATA interface.