hi there !

Opera browser does not integrates well with KDE Plasma. It shows in every workspace, in every activity, it has not have a standard windows border with the regular context menu (move to workspace; show on activity)
Is there a way to fix this ?

Opera is a proprietary browser, KDE can do nothing for this, although I seem to remember that there is an option to have the title panel, but it is possible that it has been removed, in Vivaldi, Chromium, Chrome and Brave you can activate it.