https://bugs.gentoo.org/960211
https://github.com/fltk/fltk/commit/7c93e280da4ac5aae83efeb58fb93c4cfbdee7e3
--- a/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
+++ b/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
@@ -1818,5 +1818,5 @@
   int is_a_move = (X != x() || Y != y());
   bool true_rescale = Fl_Window::is_a_rescale();
-  float f = Fl::screen_scale(pWindow->screen_num());
+  float f = fl_win ? Fl::screen_scale(pWindow->screen_num()) : 1;
   if (fl_win && fl_win->buffer) {
     int scale = wld_scale();