Custom titlebars on Linux doesn't respect system settings for titlebar button positions or style

[braydie]

• VSCode Version: 1.28.2
• OS Version: Manjaro Linux, KDE Plasma 5.13.5

Steps to Reproduce:

1. Use "window.titleBarStyle": "custom" in settings.json

Does this issue occur when all extensions are disabled?: Yes

On KDE, it appears that when title bar style is set to custom, title bar button location is not respected:

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Custom titlebar should apply to all windows (Process Explorer, Report a bug, Dialogs...) (#53282)

[braydie]

Found another comment mentioning the same - but could not find another a dedicated issue to it

#29997 (comment)

[braydie]

Closing this as it is a duplicate of #53650