Preferences: Window Icon

Thunar 4.18.6 Openbox on Arch Linux Cairo-Dock 3.4.1

When I start Thunar with "Use Current Folder Icon" off (unticked) it starts up using the current window icon. If I then tick and untick the box in preferences it changes to the thunar icon.

The expected behaviour is that when the "Use Current Folder Icon" is ticked the folder icon should be used, when it is unticked the thunar icon should be used.