diff --git a/samples/lj-demo.py b/samples/lj-demo.py
index 46173f31cbf..eeab45f217a 100644
--- a/samples/lj-demo.py
+++ b/samples/lj-demo.py
@@ -454,7 +454,7 @@ def main_loop():
         new_box = np.ones(3) * controls.volume**(1. / 3.)
         if np.any(np.array(system.box_l) != new_box):
             for p in system.part:
-                p.pos *= new_box / system.box_l[0]
+                p.pos = p.pos * new_box / system.box_l[0]
             print("volume changed")
             system.force_cap = lj_cap
         system.box_l = new_box
diff --git a/src/python/espressomd/visualization_opengl.py b/src/python/espressomd/visualization_opengl.py
index 3984349bc66..9b4b7588fe4 100644
--- a/src/python/espressomd/visualization_opengl.py
+++ b/src/python/espressomd/visualization_opengl.py
@@ -1587,22 +1587,17 @@ def _init_espresso_visualization(self):
         self.depth = 0
 
         # LOOK FOR LB ACTOR
-        if self.specs['LB_draw_velocity_plane'] or \
-                self.specs['LB_draw_nodes'] or \
-                self.specs['LB_draw_node_boundaries']:
-            lb_types = [espressomd.lb.LBFluid]
-            if espressomd.has_features('CUDA'):
-                lb_types.append(espressomd.lb.LBFluidGPU)
-            for a in self.system.actors:
-                if isinstance(a, tuple(lb_types)):
-                    # if 'agrid' in pa:
-                    self.lb_params = a.get_params()
-                    self.lb = a
-                    self.lb_is_cpu = isinstance(a, espressomd.lb.LBFluid)
-                    break
+        lb_types = [espressomd.lb.LBFluid]
+        if espressomd.has_features('CUDA'):
+            lb_types.append(espressomd.lb.LBFluidGPU)
+        for actor in self.system.actors:
+            if isinstance(actor, tuple(lb_types)):
+                self.lb_params = actor.get_params()
+                self.lb = actor
+                self.lb_is_cpu = isinstance(actor, espressomd.lb.LBFluid)
+                break
 
         if self.specs['LB_draw_velocity_plane']:
-
             if self.specs['LB_plane_axis'] == 0:
                 pn = [1.0, 0.0, 0.0]
                 self.lb_plane_b1 = [0.0, 1.0, 0.0]