Partitions in the left-side bar with the "&" symbol in their label have incorrectly-displayed tooltip on hover-over
If your disk partition has an "&" symbol in the partition label and you hover your mouse cursor over the according partition in the left-side bar in Thunar, the tooltip that is displayed will be incorrect.
The incorrect tooltip will either show the text from the previous tooltip instead (this occurs if you keep your cursor within the left-side bar) or will show a blank tooltip with no text at all as if the text was nothing more than a space as in the spacebar (see attached screenshot - this occurs if you move your cursor from the folder-view area and directly onto the according partition with the "&" symbol)
This was tested with Thunar 4.16.10 on Manjaro XFCE 21.2.2-220123 and Xubuntu 22.04 daily-bulid @ 2022-02-19 as well as with Thunar 4.16.8 on Linux Mint XFCE 20.3 and Xubuntu 21.10.
For reference, this issue does not occur in "Dolphin" on Manjaro KDE 21.2.2-220123 nor in "Files" on Manjaro Gnome 21.2.2-220123 yet, curiously, does occurs in "Nemo" on Linux Mint 20.3 Cinnamon and "Caja" on Linux Mint 20.3 Mate; I also confirmed that it doesn't occur in "Files" on Fedora Workstation 35 with Gnome.
This is probably most easily tested with a plain old FAT32-formatted USB flash drive which is what I used in the attached screenshot showing the blank "space" incorrect tooltip on Manjaro XFCE 21.2.2-220123 (that weird dark rectangle below the highlighted "MISC & CRAP" USB flash drive is in fact the tooltip):