This issue is known to occur (AFAIK) because of how Windows and the Intel drivers interact. I have this issue on both of the NUC platforms that I own. I have ~NOT~ seen it happen with external GPU's only with Intel's IGP. (This isn't a definitive test, just an observation.)
The MOST annoying part is that not only are all windows moved to the main display, but that they all get resized to 640x480 in the upper left corner.
This is more than frustrating as and desktop ICON layout gets munged and three displays of open applications all are collapsed onto the primary display. If I have had a huge number of Windows open, if I don't re-expand them to the sizes and locations I want, many of them 'think' than this is the 'new normal' and will remember the last position.
This (for me) is probably the 'least' of the major problems I am having with my NUC6i7KYK, but DOES happen on BOTH NUC platforms that I have.
- Using any combination of more than a single display (with 2x16GB memory installed) has issues (I've got more than one thread on this).
- About 5 minutes after a cold boot, the KYK 'spontaneously' resets (no BSOD) and the Firmware (BIOS) displays a message about something changing. Once past this, the machine tends to be 'mostly' stable with 16GB of memory.
- The issue you describe here.
Once the 'top two' (Really bad) issues are fixed (If they ever are) this one is at the level of 'extra annoying', but something I have just begin to accept. (Sad, but given the MONTHS and MONTHS that Intel seems to take addressing issues, this is 'typical'.)
Honestly as far as the iGPU goes I am almost to at the point of just getting Xeon processors. In a pinch the iGPU works well enough with a SINGLE display, but has many issues with multiples.
For many laptops (Other than MacBook Pro) and other 'small appliance' devices the iGPU is the only thing on offer. IF they had a good track record, many times this is just fine.
Good luck to us all in getting Intel to fix this one.
I tried out the beta drivers and it has made no difference.
I should add there are rare days I come back to my desk in the morning and find the windows have not all moved to the primary display. But I would still say the longer the displays are a sleep the more likely the windows get moved. And I find they get moved sometimes even after having only gone to sleep for a few minutes.
This message was posted on behalf of Intel Corporation
I have not been able to replicate same issue with some demos I have around.
Try getting customized drivers from Dell at: http://www.dell.com/support/home/us/en/04/product-support/product/xps-15-9550-laptop/drivers?rvps=y
Or wait for future driver releases at: https://downloadcenter.intel.com/default.aspx