I use the Vanilla-DMZ cursor theme, as described in the wiki (Cursor Themes - NixOS Wiki). This seems to work fine for most applications, although I see different cursor EXWM/emacs as opposed to other applications (e.g. qutebrowser, urxvt).
However, for GTK applications (e.g. inkscape, nm-connection-editor), there is a transparent large X as cursor, indicating that GTK applications don’t make use of the Vanilla-DMZ cursor theme…
I’ve edited /home/moritz/.config/gtk-3.0/settings.ini to contain
gtk-cursor-theme-name=Vanilla-DMZ
instead of breeze_cursors (although ‘locate breeze_cursors’ shows some occurrences in my /nix/store), but still this does not fix the problem. I have
Xcursor.theme: Vanilla-DMZ
set in .Xresources, otherwise no cursor-related settings.
Thanks in advance and please let me know if further information might be helpful