hi
i have a dell 24" monitor(wi hub) mos sets up fine wi 1900x1200
i also have a 28" hanns.g monitor wen i swapped monitors mos displayed 1900x1200. but after a meditating browser and a reboot the display has gone down to 1600x1200 and unless i change machine back to dell monitor i cant change the res back to 1900x1200, is this just a glitch i will have to live with or is there away to make the hanns.g see 1900x1200

Guess the DDC fails on the 28'' beast. In that case you should probably open the Monitor preferences, configure it manually and save that, which will disable the autodetection.