I have used Okular for many years. So far it has always seamlessly integrated with whatever DE theme I have set. It has functioned like this across many different Ubuntu releases, but not the latest:
I have searched in the preferences menus, but can not find an obvious way to tweak Okular's theme to the DE. How can it be done?
qt5-style-plugins
package but nothing changed. – Luís de Sousa Aug 17 '18 at 08:00