P2415Q, XPS 15Z, Multiple display, after sleep, applications revert to main display

You have stuff on the external monitor, the computer enters sleep, when woken up, the laptop GPU first sets itself to the laptop display, the opened windows then shunt to it, then the laptop GPU extends to the external monitor. I do not know any way to change this order. As a test, set the external monitor as the only primary display. So you are not using the laptop screen. Open the windows, allow the laptop to enter sleep, wake it up. Did the open windows look the same on the external monitor?

Hi Chris,

Yes, with the external display as the primary screen things remember their positions, but obviously items in the now secondary screen come to the primary screen....

I also don't understand why the Dell display manager app doesn't allow the configuration of all screens (maybe it does if it is another Dell screen, albeit not a screen on a Dell notebook). I can understand not being the configuration manager for all screens (because there might be non-Dell screens), however disabling the inbuilt windows ability to snap active programs to the right of left of the screen (not being managed) is a bit tiresome.

I guess I need to look at some third party app that will allow management of ALL screens...

Due to the graphics limitations of the XPS 15Z being only DP 1.1 and not DP 1.2, set the monitor OSD Display MST to Secondary 4K2K 30Hz with MST (DP out) disabled. Re-test.

Just to reiterate what I mean about scaling, normally I would have the Dell on 'Let me choose one scaling.....' 100%. If I change this to the slider option instead and select the smallest setting, on the 15Z screen I get 125% as default (in say IE) and 200% on the second screen. I guess really 100% & 150% would be ideal.

Hi Chris,

Thanks for the help. I changed the OSD MST to Secondary and it immediately changed it to 4K2K (previously had only detected a lower resolution). I set it to 30Hz in the Intel properties, but excuse the ignorance but I could not see where to change MST to disabled (screen OSD menu?).

With this higher resolution I see that the scaling is not really working. I have set it between small and half way which is a compromise that does not change the 15Z's display scaling (as far as I can tell), but icons etc are still tiny and unreadable on the second screen. Have to read up some more on this, though I can see lots of forum comments on poor scaling support in windows 8.1

Cheers,

Mark