Hi Batsal, It isn't possible to have more than one volume viewer dialog. I agree this would be very helpful and I've added it to my list of projects. There is a problem that some Chimera tools like volume eraser or volume path tracer act on the volume shown in the unique volume viewer dialog. Also I'll have to think about the user interface details of creating, hiding, and removing extra volume viewer dialogs. For now one small aid to working with multiple volume data sets is to use the volume dialog Features / Data Set List menu entry. This shows a list of the volume data sets and you can click on list entries to switch between them rather than using the more cumbersome menu of data sets. If this is frequently useful you can use Features / Save Default Dialog Settings so the data set list is shown by default. There is a bug in Chimera version 1.2304 when using menu entry File / Save PDB.... If you have one PDB model and a map open it does not offer you a choice of saving the PDB coordinates relative to the map. This is fixed in Chimera snapshot version 1.2309. You can work around the problem in 1.2304 by opening two PDB models. Then Chimera will give you the choice to save coordinates relative to the map. The second PDB model can be anything (another copy of the first model) and does not need to be saved. That's inconvenient and I recommend using Chimera 1.2309 instead. Tom