Currently, if one misclicks a unit or technology, they first need to left-click its icon from the build que to Go To relevant building, then click again from the buildings local que in order to cancel building/researching it.
Right-clicking any unit/tech icon on the global build que has no function, this could be an added QoL feature to cancel building those units.
It would be useful in scenarios when hitting the pop-cap as well, of deleting qued units when there is no population space for them.