I like what was done with the new Save As... dialog in 4.6, with 4 options to designate a target folder, rather than the logic we tried to work out in a prior version (which was never implemented right) to try to define a default folder to reduce file picking operations.
However, when I close Photo Mechanic and reopen it, my default "Save To This Folder" location is probably the first folder I ever designated after installing 4.6. That folder is long gone (moved to an archive disk). If I forget to reassign the folder PM makes that old folder again :-).
I don't know if this is the intended behavior, but I think PM should save and restore the last designated folder in the save As dialog. That way when I close PM and reopen it the default assigned folder is the last folder I worked. That is the only logical default value, short of having a preference for a default location, which might work in some work flows, but not mine because most of my save as operations are to a subfolder of my current set of original images. Because of my preferred folder structure, the "Create Subfolder" option does not quite work for me.
