Noticed in the Commodities Buy screen. The mouse works, the list will scroll and the actions will highlight and operate but the pointer is invisible. Very erratic. Will try to replicate it. Running via Wine.
It will reappear eventually but I can't work out why.
Happens on Windows too, infrequently.
I find that if your pointer is visible before you dock, then it will be visible in the dockscreen, and otherwise, it will not be.
Worked it out. The appearance of the mouse pointer was erratic.
Referring the image in the OP, if the mouse pointer is outside of the area covered by the Wind Slaver dockscreen prior to docking, it will not be visible. If the mouse pointer is inside the area that will be covered by that dockscreen, it shows in the dockscreen.
EDIT: And now I can't replicate this. It is back to the 'mouse visible before docking = mouse visible in the dockscreen'. I give up!!!