Hi Camel1918,
Apologies for not answering that earlier post. I mustn't have noticed it at the time.
Regarding multiple hits, it's treated as a separate attack, so what you say is correct.
Re 'clearing the window of attackers', I'm a little unclear what you mean. If you mean how do you remove characters or NPCs from the two lists/columns, the software is very simplistic in this regard. Just click the checkbox next to a character and hit the delete button.
Importantly, if you have more than, say, 20 NPC/creatures in your full list, it's best to use the filter functionality by assigning Keys to various subgroups of NPCs. You can then use the Name and/or Key fields in the top right to filter (display) the relevant NPCs/creatures/monsters that are of interest for a particular encounter.
For example, I assign a Key substring "E3" to all NPCs/creatures which I know are in my 3rd encounter group.
Cheers