fix screen dpi setting has no effect

Author: zisoft

src/gui/gtk.c

@@ -1630,10 +1630,10 @@ double dt_get_screen_resolution(GtkWidget *widget)
       screen_dpi = 96.0;
       strncpy(opt_str, "(default value)", sizeof(opt_str));
     }
-    gdk_screen_set_resolution(gtk_widget_get_screen(widget), screen_dpi);
-    dt_print(DT_DEBUG_CONTROL, "[screen resolution] setting the screen resolution to %f dpi %s",
-             screen_dpi, opt_str);
   }
+  gdk_screen_set_resolution(gtk_widget_get_screen(widget), screen_dpi);
+  dt_print(DT_DEBUG_CONTROL, "[screen resolution] setting the screen resolution to %f dpi %s",
+            screen_dpi, opt_str);
   return screen_dpi;
 }