Since Kevin asked for some make/Model information I will post below (slightly modified) what i already posted on social.technet.microsoft.com which contained that very information and a more detailed explaination of what and how the problem manifests itself
on my systems.
My initial setup:
IOGEAR miniview DVI 4 port USB KVMP Switch/Model GCS1764
port 1 - NVIDIA 8800 GTS Win7 beta (64bit)
port 2 - NVIDIA 8400 GS Vista Ultimate (32bit)
port 4 - ATI 9550 XP Pro
port 3 - unused
Until win7 beta was installed on the system using port 1 there had never been any problem with switching back and forth to any system. After the install of win7 beta (64bit), whenever i switched away from port 1, upon return the resolution
had reverted to 1024x768 while i was away. Most of the time the return to port 1 would return the resolution to my normal 1920x1200, but window sizes and positions had changed to accomodate the lower resolution, while i was away. On some occasions the resolution
on port 1 would remain 'stuck' on the 1024x768 and not revert until i clicked the Detect button on the change resolution window. Using the send feedback link on the beta windows i reported this issue. It did not matter where i went away to either the XP, Vista
or even the unused port, the window size and position always happened. Also to make things clearer, there were NO issues at all on the other ports' resolution, window size, position etc.
Along came the Beta RC, i installed the 32bit RC by mistake. Upon install the problem no longer existed. I was a happy camper. About a week later i discovered i had installed the 32bit RC and thought this issue was related to that. Then another week later a
new video driver came in a windows update, after install of this driver the problem returned. This problem is so annoying, i did a system restore from prior to the update, the problem was gone again. Now it seemed to have no relation to whether 64bit or 32bit,
but i was still happy with an RC that was working.
Now we arrive at October 22, and the release of Windows 7, and My current Setup:
IOGEAR miniview DVI 4 port USB KVMP Switch/Model GCS1764
port 1 - NVIDIA 8800 GTS Windows 7 Professional (64bit)
port 2 - NVIDIA 8400 GS Windows 7 Professional (64bit)
port 4 - ATI 9550 Windows 7 Ultimate (32bit)
port 3 - Dell 1525 Laptop Windows 7 Ultimate (32bit)
The situation now that windows 7 is on all systems has changed. The results are confusing to me and probably do nothing towards the resolution of this issue, but i will describe them.
port 1 This system is the one i use most and for whatever reason it has no issue. It is unexplainable but i am VERY happy that it does not exhibit any issue (so far).
port 2 EVERY switch away reverts resolution to 1024x768 and return will either revert to 1920x1200 with window sizes and positions changed, or on occasion actually be 'stuck' in the lower resolution and require a click on the Detect button to revert to normal
resolution, also on a few occasions a switch to this system results in NO VIDEO, i have to switch away again and when i switch back, video, along with the window size/position issue will have returned.
port 3 This is a laptop, and it is set to only use monitor 2, with monitor 1 being the laptop display. When switched away, the laptop display comes on which has max resolution of 1280x800. Upon return to port 3 resolution is normal 1920x1200 and window positions
etc will have changed from where they had been as a result of the resolution change. This means that even though i told windows 7 to display only on monitor 2, It decides in its infinite wisdom to freak out when monitor 2 seems to go away, and in its desperation
to display something, it finds the laptop display and switches to it . It does this without my approval and in fact contrary to my setting. Settings that do not do what they are supposed to do, are not settings!
port 4 I rarely switch to this system but when i do it has always been correct resolution etc. However after running a day or so I switch to it and find a blank screen, the monitor goes into sleep mode and i cannot awaken it. The system is running properly
but sans video. I have not probed into this issue yet. It probably is totally unrelated, and as such i am not worried about it.
I cannot explain the fact that port 1 works, as much as i cannot explain why port 2, NEVER works, the only possible explaination is the different Video Card, because yes i have switched the system on port 2 to port 3 with the SAME results. I refuse to mess
with port 1 since it for some unknown reason is working. Based on what happens on port 3, it seems to me the problem is a result of windows 7, doing what it thinks best, not what the user has told it to do. This is unacceptable to me. Why give me an option
called "show desktop only on 2" if what it really means is "show desktop on 2 unless 2 goes away then either find another monitor or just revert to some lower resolution because my main monitor is gone".
Personally i can find no rational reason WIN7 NEEDS to function like this, however given that someone with more knowledge than i seems to think that it does, there should be a setting that will allow a user to turn this function OFF should they so desire. It
would also make the OS backwards hardware compatible to Vista and XP which NEVER had this issue. Just my two cents worth. I will be monitoring for any forthcoming hacks or fixes for this very irritating issue.