diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index ca04b68322..f3181f2c06 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -1374,7 +1374,7 @@ void Sidebar::load_ams_list(std::string const &device, std::map<std::string, Ams
             ams.set_key_value("filament_id", new ConfigOptionStrings{tray.second->setting_id});
             ams.set_key_value("filament_type", new ConfigOptionStrings{tray.second->type});
             ams.set_key_value("tray_name", new ConfigOptionStrings{std::string(1, n) + std::string(1, t)});
-            ams.set_key_value("filament_colour", new ConfigOptionStrings{"#" + tray.second->color.substr(0, 6)});
+            ams.set_key_value("filament_colour", new ConfigOptionStrings{"#" + tray.second->color.substr(0, 8)});
             filament_ams_list.emplace_back(std::move(ams));
         }
     }
diff --git a/src/slic3r/GUI/WipeTowerDialog.cpp b/src/slic3r/GUI/WipeTowerDialog.cpp
index fbda4b407b..598d777846 100644
--- a/src/slic3r/GUI/WipeTowerDialog.cpp
+++ b/src/slic3r/GUI/WipeTowerDialog.cpp
@@ -493,8 +493,18 @@ static float calc_triangle_3rd_edge(float edge_a, float edge_b, float degree_ab)
     return std::sqrt(edge_a * edge_a + edge_b * edge_b - 2 * edge_a * edge_b * std::cos(to_radians(degree_ab)));
 }
 
-int WipingPanel::calc_flushing_volume(const wxColour& from, const wxColour& to)
+int WipingPanel::calc_flushing_volume(const wxColour& from_, const wxColour& to_)
 {
+    wxColour from = from_;
+    wxColour to   = to_;
+    // BBS: Transparent materials are treated as white materials
+    if (from.Alpha() == 0) {
+        from.Set(255, 255, 255);
+    }
+    if (to.Alpha() == 0) {
+        to.Set(255, 255, 255);
+    }
+
     float from_hsv_h, from_hsv_s, from_hsv_v;
     float to_hsv_h, to_hsv_s, to_hsv_v;