I just upgraded to LR 10 (Windows) and there is a new unexpected behavior. In prior versions, if I had an image selected in Library module, and then clicked over to the Develop module (or just pressed "D" keyboard shortcut) the selected image wolud open in the Develop module. That made perfect sense.
Now, with version 10, a seemingly random image opens in Development module -- not the one I have selected. It's weird. It seems to at least open an image from within the same working folder. But it's not at all what any rational human would expect.
Ah, good point. I should have scaled the thumbnails down to make it more obvious what was going on. But the opened image actually is in the folder that is displayed in grid view, it's just further down in the list so it's not showing in the screen-recording.