Would be useful to have our own cursors that are used when the pointer is on the canvas. Different shapes and synchronization across subplots, crosshairs etc would be useful.

It seems like hiding the cursor is going to be GUI framework specific, i.e. different implementation for Qt, glfw, jupyter_rfb. If we can remove the system cursor, we can use things like our own crosshairs and pointers that are custom synchronized across subplots.

For Qt it's quite simple, I can't seem to get the BlankCursor working though, but CrossCursor works:

from PyQt6.QtCore import Qt

iw.gridplot.canvas.setCursor(Qt.CursorShape.BlankCursor)
iw.gridplot.canvas.setCursor(Qt.CursorShape.CrossCursor)