Problem settings screen resolution
I have a laptop, to which sometimes I connect a secondary LCD screen (Benq FP731). This screen has a native resolution of 1280x1024. Using displayconfig-gtk, I am able to configure refresh frequency, resolution, position etc...
However, there is an annoying problem. After I save changes and restart X, the monitor uses the resolution configured using displayconfig (1280x1024), but the "virtual" X resolution is slightly larger. The consequence is that there is a hidden portion of the desktop that I can see only by "pushing" the mouse pointer towards the edges of the desktop.
I examined the xorg.conf modified by displayconfig, and I noticed that it contains a number of "fake" modes referring to resolutions that my monitor does not support (e.g. 1600x1200). I think that the large virtual desktop is caused by the presence, in the configuration file, of these fake modes. Removing these resolutions from the "Modes" line fix the problem, but it is an operation that must be done manually.
I believe it would be more correct to save in xorg.conf only the information regarding the mode that is actually used.