Fair enough. I guess I am just lazy wanting not wanting to drag an item all the way from the inventory to the quickbar or resistant to change!
I don't suppose its worth putting in a feature request for shortcut key for this? I'll take no reply as don't bother.

Thanks for the attention. The bug is in two parts.

There is no longer a shortcut for moving an item to the quickbar, expected behaviour from 0.16 is broken; at least for me I liked and used this behaviour and noticed immediately that it was missing.

The tooltip text in the settings is incorrect.

in 0.16 shift-left mouse button with player gui open transfered between player inventories effectively moving an item to the quickbar

in 0.17.36 as the quickbar is no longer another inventory nothing happens

in 0.17.36 in Settings-Controls-Inventory-Stack transfer the tooltip or blue "information ...