diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index b722dcc24..0034d2eb9 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -7028,13 +7028,14 @@ void Plater::priv::on_filament_color_changed(wxCommandEvent &event)
     //q->update_all_plate_thumbnails(true);
     //q->get_preview_canvas3D()->update_plate_thumbnails();
     int modify_id = event.GetInt();
-    if (wxGetApp().app_config->get("auto_calculate") == "true") {
-        sidebar->auto_calc_flushing_volumes(modify_id);
-    }
 
     auto& ams_multi_color_filment = wxGetApp().preset_bundle->ams_multi_color_filment;
     if (modify_id >= 0 && modify_id < ams_multi_color_filment.size())
         ams_multi_color_filment[modify_id].clear();
+
+    if (wxGetApp().app_config->get("auto_calculate") == "true") {
+        sidebar->auto_calc_flushing_volumes(modify_id);
+    }
 }
 
 void Plater::priv::install_network_plugin(wxCommandEvent &event)
diff --git a/src/slic3r/GUI/WipeTowerDialog.cpp b/src/slic3r/GUI/WipeTowerDialog.cpp
index 265ed00ce..ec4fb8300 100644
--- a/src/slic3r/GUI/WipeTowerDialog.cpp
+++ b/src/slic3r/GUI/WipeTowerDialog.cpp
@@ -350,6 +350,9 @@ WipingPanel::WipingPanel(wxWindow* parent, const std::vector<float>& matrix, con
                         str = wxString::Format(("%d"), MAX_FLUSH_VALUE);
                         edit_boxes[i][j]->SetValue(str);
                     }
+                    else if (value < 0) {
+                        edit_boxes[i][j]->SetValue(wxString("0"));
+                    }
                     });
 
                 auto on_apply_text_modify = [this, i, j](wxEvent &e) {