Your explication make sense to me, but I don’t think that the current behavior match exactly what you expect.
It look like, at least when tab_completion is active, ctrl+space always trigger the second best completion rank, whatever you press tab before or not.
I suppose that this behavior only make sense if the last command was an “insert_best_completion”, so in this example the correct completion is “vDocNumber”, isn’t it ?
type vdoc
ctrl+space -> vComNameDOC
And the second glitch is that in my list, for “vdoc” the best completion is clearly “vDocNumber”, but the two others must be almost at the same level.
So I think in this case the popup must be shown.
type vdoc
tab -> vDocNumber
ctrl+space -> vComNameDOC
It look like ST make the decision to not show the popup based not on the remaining items in the list, but on the complete items list.
In this context ST must look at the remaining items (vComNameDOC, vGcoNameDOC) and because the rank is almost the same show the popup.
Hope I was clear.
Thanks for your time.