how to NOT see computers in the "Shared" sidepane

Is there a way to NOT see a computer in the Shared sidepane under "All..."

Long story short, we used to live together, now we don't. But I still see her computer on my "network." A picture is worth a thousand words. Any way to not see this when that computer is online?

 

Hm, thanks. I can't imagine it's a reboot problem. This has been going on for probably 9 months. I've done updates that required reboots and the router has been reset several times during that period too.

It's not there most of the time, but every once in a while I see it. Sometimes it's her iMac instead. I assume that's because we're not usually online at the same time.

I was hoping to be able to not see it without emailing the owner and telling her to remove me from her Screen sharing preferences. But it's not a big deal so I'll probably just ignore it.