lightdash: Panel plugin multiple linkage issue

[adlo]

I am writing an Xfce panel plugin. It can be found at https://github.com/adlocode/xfce4-lightdash-plugin

When building with GTK2 it works, but when building with GTK3 it seems to hang at the first point that any GTK3-specific code is used. It generates error messages such as "cannot register existing type 'GtkWidget'". This seems to suggest that it is linking to both the GTK2 and GTK3 libraries, but I can't find anything obvious.

Any ideas on how I could solve this?

Regards

adlo