I cannot reproduce this on KDE Neon with Okular 22.11.70 following the same steps. After setting the background color, my okularpartrc contains this:
[PageView] BackgroundColor=255,85,0 UseCustomBackgroundColor=true
After disabling the background color, my okularpartrc changes to this:
[PageView] BackgroundColor=255,85,0
And Trim Margin still works whether I then restart Okular or not.
I cannot reproduce this on KDE Neon with Okular 22.11.70 following the same steps. After setting the background color, my okularpartrc contains this:
[PageView] =255,85, 0 oundColor= true
BackgroundColor
UseCustomBackgr
After disabling the background color, my okularpartrc changes to this:
[PageView] =255,85, 0
BackgroundColor
And Trim Margin still works whether I then restart Okular or not.