Hi Luca, We have all done similar things… very sorry! Despite its importance and usefulness, it is a big task to add undo support, and we are now devoting resources to ChimeraX development rather than Chimera. We are working on undo for ChimeraX. It is somewhat limited, but we intend for most common display, style, and coloring changes to be undoable. Current “undo” description in ChimeraX: <http://rbvi.ucsf.edu/chimerax/docs/user/commands/undo.html Best, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

On Nov 27, 2019, at 7:27 AM, Luca Pellegrini <lp212@cam.ac.uk> wrote:

I was wondering if there are any plans for an Undo option? I just managed to wipe a detailed view of an active site with lots of side chains, by selecting one more amino acid on the ribbon drawing and then picking by mistake ’show only’ rather than ’show’ (slip of the finger).

ps: I found an old post on this in 2004, explaining that there is no such option, but perhaps the Chimera authors are open to changing their mind? After all, we are using Chimera to make ever more complex drawings.

Best wishes, Luca