Wrong theme selected for Qt5 applications

[RazrFalcon]

I use KDE4 with dark theme + Gentoo. After building appmenu-qt5 from source (bzr latest ver., with or without KDETHEME_STILL_PRIVATE), all Qt5 apps start's to use white theme, not dark.
Examples in attachments.

Can I fix it?

[Rik Mills (rikmills)]

Finding the same thing with the main repository packages in utopic and vivid.

Most qt5 app seem to theme OK, but several do not, ignoring any dark or other colour scheme. Notably here calibre and qterminal.

Removing the appmenu-qt5 restores correct themeing.

[Fighter19 (littlefighter1996)]

In combination with a Ubuntu+Kubuntu netinstall this also results that you can't select any theme on KDE5 (well you can, but it won't have any effect). Instead only GTK+ will be chosen.