I want to click and drag the boat to the slot that has the iron nuggets, and then move the iron nuggets elsewhere, but the hotbar slots are locked, so I have to drag to boat to another slot, then close the backpack and only then I can move the boat to a hotbar slot.

If the idea is to prevent the moving of the backpacks while they are opened, maybe locking the whole hotbar seems like overkill, just lock the opened backpack slot.

Spinnery issue, fixed in 2.1.2-beta.