I've just seen that there is a german messages in the shell-output telling that there is a gtk-engine missing, but I think I have unstalled all gtk-enginges, which are needed:
$ pkg info | grep gtk
gtk-update-icon-cache-2.24.32 Gtk-update-icon-cache utility from the Gtk+ toolkit
gtk2-2.24.32 Gimp Toolkit for X11 GUI (previous stable version)
gtk3-3.22.30_1 Gimp Toolkit for X11 GUI (current stable version)
gtkimageview-1.6.4_5 Simple image viewer widget
gtkmm24-2.24.5 C++ wrapper for Gtk+
gtkmm30-3.22.2 C++ wrapper for Gtk+3
gtkspell-2.0.16_6 GTK+ 2 spell checking component
libcanberra-gtk3-0.30_4 Implementation of the Freedesktop sound theme spec
plasma5-breeze-gtk-5.12.5 Plasma5 Breeze visual style for Gtk
plasma5-kde-gtk-config-5.12.5_1 Plasma5 GTK2 and GTK3 configurator
py27-gtk2-2.24.0_5 Set of Python bindings for GTK+
webkit-gtk2-2.4.11_17 Opensource browser engine using the GTK+ 2 toolkit
webkit2-gtk3-2.20.5 Opensource browser engine using the GTK+ 3 toolkit
wx30-gtk2-3.0.4_3 The wxWidgets GUI toolkit with GTK+ bindings
$
I've just seen that there is a german messages in the shell-output telling that there is a gtk-engine missing, but I think I have unstalled all gtk-enginges, which are needed:
$ pkg info | grep gtk icon-cache- 2.24.32 Gtk-update- icon-cache utility from the Gtk+ toolkit 1.6.4_5 Simple image viewer widget gtk3-0. 30_4 Implementation of the Freedesktop sound theme spec breeze- gtk-5.12. 5 Plasma5 Breeze visual style for Gtk kde-gtk- config- 5.12.5_ 1 Plasma5 GTK2 and GTK3 configurator gtk2-2. 4.11_17 Opensource browser engine using the GTK+ 2 toolkit
gtk-update-
gtk2-2.24.32 Gimp Toolkit for X11 GUI (previous stable version)
gtk3-3.22.30_1 Gimp Toolkit for X11 GUI (current stable version)
gtkimageview-
gtkmm24-2.24.5 C++ wrapper for Gtk+
gtkmm30-3.22.2 C++ wrapper for Gtk+3
gtkspell-2.0.16_6 GTK+ 2 spell checking component
libcanberra-
plasma5-
plasma5-
py27-gtk2-2.24.0_5 Set of Python bindings for GTK+
webkit-
webkit2-gtk3-2.20.5 Opensource browser engine using the GTK+ 3 toolkit
wx30-gtk2-3.0.4_3 The wxWidgets GUI toolkit with GTK+ bindings
$