Transform Properties panel in 3d window. New button "Parbone" showing when parent relation is to a specific bone. This information was nowhere reveiled in the UI until now. Code remark: The code isn't getting more beautiful now with all if() options added. The idea to move the rotation buttons down when a parent bone was set isn't very good, buttons should stay as much as possible on the same location. However, I dont have time for a solution either...