Matcha-gtk-theme
Matcha-gtk-theme copied to clipboard
Visual bug in gnome-tweak
If we moved the windows controls from right to left we have strange behavior: the left menu disappears and we have to resize the gnome-tweak for seeing again. This behavior is notable only with matcha theme; with, for example, mojave-dark-solid-alt we don't see this. See the pictures:
matcha
mojave

In case it helps, adwaita has the same issue with tweaks.
This behavior is related to libhandy, as far as I know. You can reproduce this with any other theme if you resize the window to some smaller width. Maybe making some of the components of the theme smaller would fix this, but if Adwaita also causes this behavior, in my opinion it's a bug in gnome-tweaks that can be fixed if the default width of the window becomes set to a higher value.
All of the themes I have ever used have all had this problem. It is probably not related to themes at all.