fix issue where items on building's output port were not counted to output display in building panel

src/ui/SelectedBuildingPanel.cpp

@@ -479,13 +479,24 @@ void SelectedBuildingPanel::refreshBuffers(const Building* b)
         bufText += "\n";
     }
 
-    if (recipe && !recipe->outputs.empty())
+    // Count output-side items: buffered plus still-emerging on the output belts.
-    {
+    // An emerging item still belongs to the output buffer (REQ-MAT-OUTPUT-EMERGE),
+    // so it must be included here or it would vanish from the panel while animating.
     std::map<std::string, int> outCounts;
     for (const Item& item : b->outputBuffer.items)
     {
         outCounts[item.type.id]++;
     }
+    for (const std::vector<BeltItemSlot>& lane : b->emergingItems)
+    {
+        for (const BeltItemSlot& slot : lane)
+        {
+            outCounts[slot.item.type.id]++;
+        }
+    }
+
+    if (recipe && !recipe->outputs.empty())
+    {
         bufText += tr("Output: ");
         for (const RecipeOutput& out : recipe->outputs)
         {
@@ -497,13 +508,8 @@ void SelectedBuildingPanel::refreshBuffers(const Building* b)
                 + "/" + QString::number(out.amount) + "  ";
         }
     }
-    else if (!b->outputBuffer.items.empty())
+    else if (!outCounts.empty())
     {
-        std::map<std::string, int> outCounts;
-        for (const Item& item : b->outputBuffer.items)
-        {
-            outCounts[item.type.id]++;
-        }
         bufText += tr("Output: ");
         for (const std::pair<const std::string, int>& entry : outCounts)
         {