when the editor offers the proposals, user can choose not to select any.
My point is:
the proposal only applies when there is no one has been selected.
XXsomethingXX <somthing which can be selected from proposals> (if selected, then ctrl+space won't trigger any proposal again after that, if I cannot know which proposal has been selected, I need to check part within <> to ensure that)
for another example:
if i have pseudo-grammar : component.resource operation-option
operation-option can be set() or add().
when user select set can get C.R set("a")<if ctrl+space after this won't trigger any proposal, so there is no more operation when one has been picked>