#1 Display issues

[mimic]

I have a Dell monitor and a HDTV (720) connected to my Windows 10 computer.
Dell is horizontal - DVI
HDTV is vertical - HDMI
When I turn on the computer and Dell monitor is ON, Windows sees it as Display 1. Unfortunately when I turn on the TV, Windows assigns #1 to TV!!!! Rather than monitor, which is really infuriating . Even though my monitor is set as the "Main Display" When I try to change to clone displays Windows takes orders from the HDTV and tries to switch view on My main display from horizontal to vertical instead of forcing the TV to display horizontally on vertical screen. It used to work correctly on Windows 7 and even on Windows 10 , but at some point something got messed up.
On top of that MAME won't load correctly. Because of wrong order all versions hang when launched. Also because of the wrong order MAME was showing settings screen on wrong monitor when launched and I know it's not MAME but Windows, because MAME works just fine when only one screen is turned on. HDTV is mounted vertically, but I want it to display horizontally on Vertical panel in cloned mode. Used to work so on the Horizontal I can have game displayed horizontally and then on the vertical it will clone the same display but horizontally. POS Windows refuses to do it right.
What can I do? All I find is how to change the monitor I want to be the "Main Display" while I need the main display to be #1 not #2 and that I cannot change!

How does Windows allowing to take priority on 720 display it's absolutely ridiculous!

[meyer980]

I know what you're dealing with and sadly don't have a great answer. BUT, if your situation allows it, try switching which ports the displays are plugged into on your PC.

I have no evidence to this, except my one anecdotal case, but I think the identity numbers are at least partially based on hardware ports

[Mr. Peabody]

@mimic: I think the PC is not taking orders from any device. Rather the video drivers are preferring an input over the other, and that is your point of address.


@meyer980: with dual video ports (VGA/DVI) that is the case.

[mimic]

I didn't mean like taking orders, but the fact that lower resolution screen was defaulted as #1 and #2 was trying to match the resolution and orientation of the lo-res was infuriating. It should be ENTIRELY up to user which monitor is #1 if setting "Main Display" is not sufficient. Connectors deciding order is totally ridiculous.