default colormaps for loaded Additional Images

[J B]

Hello all, before I discovered how to save a workspace, I had been noticing that sometimes when I loaded an 'Additional Image', it got pinned as an overlay and got the same colormap I had been using at some previous time instead of default 'gray' colormap. Note, I hadn't yet used save workspace, this was somehow happening independently of save workspace. It was something somehow being saved, and acting as a default. But I can't reproduce it, it only ever happened randomly and I never understood why when it happened. 

Now, that is actually an option I would like to see, that additional volumes can get a particular colormap that is assigned automatically according to where they are in the stack of additional volumes. That would be similar to a saved workspace file I suppose, but without the specific datasets listed. Thus, it could be one file that applies to any number of working datasets. Does anyone know how I might have been seeing this behaviour for a random few datasets, and how I can get it for all datasets? thanks!