For testing purposes I installed an vanilla Manjaro XFCE and changed the theme colors from Manjaro green to Matcha azul and even there VLC doesn’t work as expected.
Unfortunately I can’t share neither pictures nor links so I don’t know how to add my screenshots
VLC and VirtualBox are Qt-based applications, while XFCE is based upon the GTK widget toolkit.
Make sure that you have qt5ct and kvantum-qt5 installed ─ they’re both in the main repository if they’re not on your system already ─and then you can tweak the look & feel of Qt-based applications.
kvantum-qt5 ─ listed in your menu as Kvantum Manager ─ is a theme engine based upon scalable vector graphics, in which you can load special Kvantum themes. There are several such themes in the repository, such as kvantum-matcha, and others can be downloaded from store.kde.org.
Thank you
I actually wanted to write that myself but was already so tired and annoyed by my problem that I forgot to do it.
Blockquote VLC and VirtualBox are Qt-based applications, while XFCE is based upon the GTK widget toolkit.
Ah, I see, this makes things a lot clearer!
Blockquote
Make sure that you have qt5ct and kvantum-qt5 installed ─ they’re both in the main repository if they’re not on your system already ─and then you can tweak the look & feel of Qt-based applications. kvantum-qt5 ─ listed in your menu as Kvantum Manager ─ is a theme engine based upon scalable vector graphics, in which you can load special Kvantum themes. There are several such themes in the repository, such as kvantum-matcha , and others can be downloaded from store.kdeorg.
Alright, coming from Xubuntu originally I wasn’t really aware of what I can do with Kvantum, so I watched two or three tutorials. Though my theme did not show up in Kvantum I somehow managed to apply it to all the programs I tested so far.
So thank you for your useful hint!
Oh, one more question since I couldn’t answer it so far: Is it advisable to use KDE Kvantum themes with XFCE?
Well, Kvantum themes only work with Qt-based applications, so they have no effect on XFCE itself. But if a Kvantum theme helps better integrating the look & feel of Qt-based apps in the XFCE environment, then I don’t see why you wouldn’t use them.