I'd like to suggest that chimera.openModels.{open,add,close} all automatically run chimera.update.checkForChanges() as they finish (suppressable by supplying a 'checkForChanges=False' keyword argument to the functions). Right now, developers who aren't "in the know" will write scripts that loop through structures, opening and closing them and performing operations, and because they don't know to call checkForChanges the scripts will typically fail due to running out of memory. Also, some other operations (surfacing) will fail if checkForChanges isn't called after a model is opened. There are other times when checkForChanges needs to run, but those are relatively rare compared to these openModels functions. It seems to me that making this change makes normal scripting less error-prone while allowing for the uncommon case of wanting to suppress the checkForChanges. Opinions? Eric Pettersen UCSF Computer Graphics Lab pett@cgl.ucsf.edu http://www.cgl.ucsf.edu