Monitor VGA PC detection

[Arty.lv]

Hi.

I have a following situation - I have a PC test bench monitor (large digital signage display) with all the video inputs one can have, HDMI, DP, DVI, VGA, Composite. But VGA input is only via DVI connectors analog pins. Since I want all the input cables connected permanently, so they are always ready when I need them, I bought a simple splitter - DVI to DVI and VGA (https://www.amazon.de/gp/product/B07KXSSQFM/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1).
The problem is, DVI input works only when VGA cable is also connected to a PC. It can even be a different computer. With single DVI->VGA or DVI->DVI cable everything works fine. My first guess was that the splitter has some missing grounds on the DVI input connector, but grounding all GND pins on VGA side did not help. Any ideas what signal it might be missing, ond/or how to make a terminator for vga cable, so the display thinks there is a PC connected to it?

[DiTBho]

Composite? X_______X

[Arty.lv]

Nevermind.
Problem solved... I just cut up some cables and made my own splitter, shoud have done this from the beginning, instead of buying chineese crap.