I have made several tests and I think the driver has any problem with the EDID information from the display.
I have put a converter beetwen the graphic card and the secondary projector that change the EDID information and the driver changes the resolution of the monitor but now to 1600x1200!.
The same PC / the same application / the same monitor and the driver does a different thing??
Any idea of what can I test?
But this effect only happens if you force FULLSCREEN mode in DirectX.
I have a projector connected as secondary monitor to the intel graphic card using HDMI cable.
I have my application working in windowd mode in 1400x1050@60Hz (native mode of the projector and all is OK). If I select fullscreen mode with 1400x1050@60Hz automatically the driver change to 1080p???.
With the same system PC+projector but using an adapter in the projector to connect with the graphic card, a converter from HDMI to 'ethernet' and from ethernet to HDMI the effect is different: The driver always goes to 1600x1200 automatically. The only change I have detected is the EDID information has change.
The resolution of your secondary is 1400x1050 - what is the resolution of your primary?
Also, if the max resolution is 1400x1050, and that is what it's displaying at in windowed mode (ala windowed fullscreen) - is it a gamebreaker to disable the fullscreen and leave it in windowed (just curious)? It sounds like your app is not set to override the operating system (which is what automatically sets resolutions, and may be causing your projector to display at 1080p).
However, I'm not an expert at this kind of software. I would suggest looking over in the Visual Computer Source/Developer Zone here (specifically in their forums but the rest of the site may be useful to you); http://software.intel.com/en-us/vcsource