Running on 12.04 after upgrading this week, I've also taken advantage of low UK priced 18.5" monitors to compliment my current Acer 20" LED X203H (1600*900) and bought an LG 18.5 LED (1366 x 768) for my desktop computer (not laptop). Put simply, I want to keep the Acer as my primary (in front), and the LG as my secondary to my left on my desktop.
But simple as this kind of issue is, I appear to get problems in making 2 monitors of different resolutions to do best (problem was the same also pre-upgrade in 11.10). I'm using ATI Catalyst on an exPress VGA card, a Asus dual head EAH4350 (512mg ram/ATI Radeon HD 4350 GPU) and ONLY using VGAs. It works fine when using a single monitor of either of the above, but trys to force the Acer 20" to 18.5" or simply gives the errors as shown in the screenshots below:
I'm keen to have the LG to my left as a secondary monitor as opposed to a 'continuous' desktop so ideal for viewing research/reference documents, study etc or programming to my left/web online directly infront. Any advice on resolving this issue is greatly appreciated. Thanks.