Clicking the Rigging Tool messes up the existing bones

I’ve got a figure rigged with bones. While animating, I often click in the toolbar on the button ‘Show the selected deformation chain and hide all others’. So far so good.

But sometimes I click by accident on the button next to it, the button ‘Rigging Tool’. And than all the bones get messed up. And the worst part of it is that I can’t undo to get the bones right again. All I can do is go back to my previous saved version of the scene.

Is there anything I can do, that - when I click by accident on the Rigging Tool button - all my work on bones will not be deleted?

Harmony Premium v.15.