Canta is a flat Material Design theme for GTK 3, GTK 2 and Gnome-Shell which supports GTK 3 and GTK 2 based desktop environments like Gnome, Unity, Budgie, Pantheon, XFCE, Mate, etc.
The 3 dots that is the Activities button are black in Canta (all variants except dark and light) and thus invisible on the black top bar in GNOME Shell.
The 3 dots that is the Activities button are black in Canta (all variants except dark and light) and thus invisible on the black top bar in GNOME Shell.
Same bug as https://github.com/vinceliuice/Canta-theme/issues/8