If I lock an object and go to the Layers panel, there is a padlock icon against the locked object. When I hover over the icon, a 'Lock/Unlock' tooltip is displayed, suggesting that clicking once on the padlock will unlock the object and then clicking it again will lock it. However, instead of redrawing in an unlocked state on the first click, the icon disappears altogether.
Suggestion: Either the padlock should remain visible so that it can be clicked again, or the tooltip should be changed to read 'Unlock'.