When I start nvidia-settings in Terminal I get this, what can be the cause of this:
ERROR: Error querying target relations The program 'nvidia-settings' received an X Window System error. This probably reflects a bug in the program. The error was 'BadRequest (invalid request code or no such operation)'. (Details: serial 214 error_code 1 request_code 156 minor_code 29) (Note to programmers: normally, X errors are reported asynchronously; that is, you will receive the error a while after causing it. To debug your program, run it with the --sync command line option to change this behavior. You can then get a meaningful backtrace from your debugger if you break on the gdk_x_error() function.)
I checked in Synaptic the version of Nvidia-settings installed is 331.20 nvidia-304-updates and recommended driver for my hardware is 304 could be because of this that I'm using newer nvidia-settings with an older driver installed? Should I install nvidia-settings 304? I ran
--sync option provided in description but the error persists to appear. Tried to completely re-installed nvidia-settings and still the same, maybe it be developer's bug.