Often when I close a file in a split view the focus goes to the other view. Some other times the view is closed too, even when there are still opened documents. A very few times, the view is not closed and the focus stays there, which is the behavior I would expect.
I could not reproduce with a few tries. Could you test with the latest version? Arch Linux 64-bit Kate 16.04.2 KDE Frameworks 5.23.0 Qt 5.7 xcb wm
Right now I'm stuck in KDE4, so I can't try thi anymore. If you say you can't trigger the situation, then I'm closing this. If I manage to upgrade to KDE5, then I'll try again and eventually give more info.