Code:
$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 002: ID 046d:c001 Logitech, Inc. N48/M-BB48 [FirstMouse Plus]
PS:
if you change killall -SIGNAL nickel with kill -SIGNAL $(pidof nickel), epub problem doesn't happen anymore. Probably some subprocess is not happy to be paused. EDIT: mh, nothing, it seems to not work anymore...