The circle is constantly red (reads “offline” on hover)
You can ignore this one for now, it’s not indicative of the actual status of the Kernel at the moment 
For stopping training, there it will always be a bit of a delay because it needs to finish whatever batch or process it’s on, but after that it should stop.
I’ve placed a ticket to look into it more though to see if there is something which doesn’t quite stop as it should.
I’ve placed a ticket to look into the issue where you can’t get the statistics view to re-appear again as well, or at the very least to make sure that you don’t get automatically logged out.
Will keep you updated as things roll in, and thanks for reporting the issues! 
Edit: Quick update, I just tested starting training and then tried:
- refreshing the frontend
- manually logging out and in again
- restarting the browser
and I could see the statistics view again afterwards without issue.
It can be that it’s because long updates between each update, would you mind trying the same issue on a smaller dataset and see if it happens there?
For example the mnist_data that comes with the tool, and just set epochs to something large so you have time to try it out.