Optistatus
What is it for?
Optistatus is a little applet for the taskbar that shows if the NVIDIA-Optimus-Card is running.
Does it work with primusrun?
Yes, because it checks the status of /proc/acpi/bbswitch, which shows if the cards is on or not,regardless if you use optirun or primusrun for launching your app
Bugs
There shouldn't be any...at least i hope so.