Selections

I placed this here, as it is a general question about selection method, as it is not just NVIL that does this, but have never really understood the logic.

I will just keep to 2 edge selection methods to keep it simple.

When using LMB to select an edge, it will select a single edge. If I was then to select a different unselected edge, it will select that, and de-selected the previous selected edge. That makes sense to me, as it is intended to only select a single edge.

Now my confusion.
If I select a single edge, then continue selection with "Shift+LMB", that is to add or remove from current selection. So if I select an unselected edge, it will be added to current selection, if I select a selected edge, that will be removed from current selection. OK so for. Now, while still in the add/remove selection method "Shift+LMB", I make a number of selections, if I then inadvertently miss selecting an edge (I click in empty space) all the previous selection are deselected, Why? When I am in add/remove to/from selection and I select nothing, should that not be a case of not adding or removing anything from current selection?

Hope that is understandable?

Any thoughts?

Thank you very much IStonia for changing the selection method.