Dual display setup: Force windows to open on the primary display

Hello, I have a dual monitor setup (two identical monitors running the same resolution). One is in front me (primary monitor) and the other one on my left. The one on my left, it’s only there to monitor stuff, so no active work. All the work I do is on the primary monitor.

My problem is that about 50% of the time, windows (main application windows and sub windows of applications) will open on the secondary window. These are 32" displays so I have to stretch my head just to look where it opened and bring the window back to my primary monitor.

Running KDE with KWin as the window manager. I tried a couple of KWin scripts that open the windows on the display that has the focused window but they didn’t work either.

Ideally, I would want sub windows to open in the center of their parent window.

Any solutions?

@ReverantGR:

In KDE Plasma System Settings, Window behaviour, Extended – there’s a setting to allow windows to remember their position – provided that, the window supports this option.

That’s great for windows that I have opened, moved to the primary display and then closed. But there are myriads of windows that I open for the first time and it gets really old really fast.

Is there no option to force everything to open on the display I want?

I use multi monitors and the way I do is. The first time I open an application and it goes to the monitor that I don’t want it to show, I grab it to the monitor
where I want it to be then right click the top and use the special window settings to force the application to where I want it next time I open it.

That works but only for the first/primary window of the app. Sub windows still open on the secondary window.

You have to use “force” to open in that display. All the same app should open in one display, unless the one you’re opening is a different app from the open app.
example: Dolphin is set to force to open in the display intended to appear but the document you open inside dolphin will be open with libre office, the result is
libre office might open in another display if it is not configured to “force” open in the intended display you want. Using force also you will not be able to move
the application anywhere so you have to set the window size if memory serves.

All the applications I am using appears on the display where I am working and applications I use as references for the one I am working with opens in another display.

This KDE thread may be of interest to the OP…
https://forum.kde.org/viewtopic.php?f=111&t=166975
…and this perhaps…
https://store.kde.org/p/1617641