There doesn't appear to be a way to remove blueprints from the numbered quick selector. I have deleted the blueprint but it is still there assigned to the button.
#[0.0.7] Blueprint stuck in quick-selector after delete
livid quest
If you hit the refresh button, it should go away. This should be fixed in 0.0.8
grave falcon
You can also right-click the one on the bar at the bottom, and it will take it off the bar.
tender void
If you hit the refresh button, it should go away. This should be fixed in 0.0.8
That didn't work, but it went after a while. Okay now I know to right-click.