The blue busy bar doesn't appear until the first busy message from the kernel. This leaves the user wondering what's happening while the kernel is spinning up.
Perhaps we should show the progress bar either before requesting a new kernel or immediately after the server responds that the kernel has been started (whichever fixes the issue and doesn't show a spinner indefinitely when there's an error.)
The blue busy bar doesn't appear until the first busy message from the kernel. This leaves the user wondering what's happening while the kernel is spinning up.
Perhaps we should show the progress bar either before requesting a new kernel or immediately after the server responds that the kernel has been started (whichever fixes the issue and doesn't show a spinner indefinitely when there's an error.)