Stumped by browser preview

I have SD3 open using a template, and whenever I try to browse different drum loops and try them out with my song, it seems to work for a while, but then I get a problem that I don't know how to fix.

I always leave one or more open measures at the start of my songs.  Well, after I browse a few loops, one of them will start playing over the open measures and I can't get it to stop.  I haven't dragged the loop onto the MIDI track, and there are no midi notes visible.  I can't even tell which track the sound is coming from but the loop plays when I play the song.

I even tried deleting the open measures and then re-inserting them from the project menu, but it still played. 

I'm not really a newbie at Sonar, but I haven't used X1 much, and I have used MIDI loops very little, so probably I'm missing something obvious.  But I'm completely baffled.

Thanks for any help.

To me what it seems like is what you are previewing in the browser is being played, check out and see what bus you have the preview browsers routed to if you have it routed .. also in the Console view mute each track and see whats playing make sure to look in the bus section..

is the play button highlighted in your browser?

Play button is not highlighted now.  I tried clicking the play button a few times.

Yes, the drum bus and master bus meters both light up.

No hidden tracks.  Thought you were onto something, because I rarely think of hidden tracks.

Nothing.

I have seen it happen on other projects, although this is actually the first time I've worked on a Sonar project in a couple of months.

You know, I don't think it's a matter of me accidentally hitting a weird button or accidentally dragging a loop into a weird spot.  This happens repeatedly.  The only way to get it to go away is by hitting ctl-z until the SD3 template disappears, but that means I have to start from scratch and can't keep my work, so having to do that repeatedly is not really a working solution.

I thought it might have something to do with dragging a loop into the clips pane while a preview was playing, and I got it to not screw up for a few minutes by stopping the preview before I would drag a clip.  But eventually it happened again, I'm not sure why, but I have become increasingly careful not to do extraneous things with my mouse so I definitely wasn't clicking on a bunch of unnecessary crap.

In the SD3 GUI is the play arrow higlighted(light grey) as well as the loop(both on the bottom row of the GUI)?
If so that will be the source of the problem.  It will play whatever sample you had previewed with it turned on.