'-popupwindow' no longer works?

[draeath]

I switched from using the 'launch arguments' method to KSSL and this argument stopped working.

Strangely, if I check the process details, I do see the command line argument. Looking at how you handle and pass along the arguments, I have no idea how this might not be working correctly, except some tiny feedback that perhaps you should use Join(String, String[]) instead of text = text + " " + str; or such. But that shouldn't be relevant and is more a style choice? I made sure that applies all the way back to Framework 3.0 :D

"../KSP_x64.exe" -popupwindow

[BitBlitObviMormon]

I'm using that too, but it seems to work for me. I'm using these command line arguments on the steam launcher:
-popupwindow -adapter 2

[RebootedDuck]

I have the same issue, no idea how to fix currently

[R-T-B]

Hmmm. That is very odd. Do both releases I've made behave the same in this regard?

I'll look into this but honestly, as you said, it should be working. I have very little direction with which to hunt this bug. But I'm looking into it.

EDIT: Wait, are you using "../KSP_x64.exe" as one of your command line parameters? Drop that if so. That'll mess things up. We haven't had to do that since like ancient days.

I assume this wiki's outdated info got you:

https://wiki.kerbalspaceprogram.com/wiki/Startup_parameters

Just list the parameters you want in steam, nothing else.