The new lock in docker is great to not accidentally close or move a docker I propose a different kind of lock or a "sticky" mode for a floating docker. When in canvas mode this docker would not go away if toolbox and palettes is marked to hide Alternatively you could just have extra options in the settings,that might be easier -floating windows (treat those differently then dockers and toolbox)
This is too similar to the hotkey to show dockers floating, so closing.