From c0846c53d766cdd02d82c64747ba6a4f5ced51ba Mon Sep 17 00:00:00 2001
From: Hecklezz <tj8@live.com.au>
Date: Wed, 12 Aug 2026 03:30:06 +1000
Subject: [PATCH] [FIRE-36910] Fix crash when dragging onto the add button for
 custom inventory tabs

---
 indra/newview/fsinventorycustomtabs.cpp | 45 +++++++++++++++++++++++++
 indra/newview/fsinventorycustomtabs.h   |  3 ++
 indra/newview/llpanelmaininventory.cpp  |  6 ++++
 3 files changed, 54 insertions(+)

diff --git a/indra/newview/fsinventorycustomtabs.cpp b/indra/newview/fsinventorycustomtabs.cpp
index 17ada047f0..5e515593f1 100644
--- a/indra/newview/fsinventorycustomtabs.cpp
+++ b/indra/newview/fsinventorycustomtabs.cpp
@@ -219,6 +219,20 @@ bool FSInventoryCustomTabs::handleMouseDown(S32 x, S32 y)
     return true;
 }
 
+bool FSInventoryCustomTabs::handleDragAndDrop(S32 x, S32 y)
+{
+    S32 local_x = 0;
+    S32 local_y = 0;
+    auto* inv_panel = hitTestAddTab(x, y, local_x, local_y);
+    if (!inv_panel)
+    {
+        return false;
+    }
+    // Drag and drop onto the Add button should not do anything
+    // Return true here to prevent calling LLPanel::handleDragAndDrop
+    return true;
+}
+
 void FSInventoryCustomTabs::onFilterFocusLost()
 {
     if (mParent)
@@ -479,6 +493,12 @@ bool FSInventoryCustomTabs::handleMouseDown(LLPanelMainInventory* parent, S32 x,
     return self && self->handleMouseDown(x, y);
 }
 
+bool FSInventoryCustomTabs::handleDragAndDrop(LLPanelMainInventory* parent, S32 x, S32 y)
+{
+    auto* self = instanceFor(parent);
+    return self && self->handleDragAndDrop(x, y);
+}
+
 void FSInventoryCustomTabs::onParentDraw(LLPanelMainInventory* parent)
 {
     if (auto* self = instanceFor(parent))
@@ -1232,6 +1252,31 @@ LLInventoryPanel* FSInventoryCustomTabs::hitTestCustomTab(S32 x, S32 y, S32& tab
     return inv_panel;
 }
 
+LLInventoryPanel* FSInventoryCustomTabs::hitTestAddTab(S32 x, S32 y, S32& tab_local_x, S32& tab_local_y) const
+{
+    if (!mTabs || !mParent || !mAddTabPanel)
+    {
+        return nullptr;
+    }
+    tab_local_x = 0;
+    tab_local_y = 0;
+    if (!mParent->localPointToOtherView(x, y, &tab_local_x, &tab_local_y, mTabs))
+    {
+        return nullptr;
+    }
+    const S32 idx = mTabs->getTabContainedAtPoint(tab_local_x, tab_local_y);
+    if (idx < 0)
+    {
+        return nullptr;
+    }
+    auto* inv_panel = dynamic_cast<LLInventoryPanel*>(mTabs->getPanelByIndex(idx));
+    if (!isAddTab(inv_panel))
+    {
+        return nullptr;
+    }
+    return inv_panel;
+}
+
 void FSInventoryCustomTabs::decorateCustomTabButton(LLInventoryPanel* panel)
 {
     if (!mTabs || !panel)
diff --git a/indra/newview/fsinventorycustomtabs.h b/indra/newview/fsinventorycustomtabs.h
index 5822b82ce3..331875d57f 100644
--- a/indra/newview/fsinventorycustomtabs.h
+++ b/indra/newview/fsinventorycustomtabs.h
@@ -52,6 +52,7 @@ public:
 
     bool handleRightMouseDown(S32 x, S32 y);
     bool handleMouseDown(S32 x, S32 y);
+    bool handleDragAndDrop(S32 x, S32 y);
 
     void noteActivePanel(LLInventoryPanel* panel);
     void notifyActiveFilterStateChanged();
@@ -81,6 +82,7 @@ public:
     static void notifyIfFilterChanged(LLPanelMainInventory* parent, S32 prev_generation);
     static bool handleRightMouseDown(LLPanelMainInventory* parent, S32 x, S32 y);
     static bool handleMouseDown(LLPanelMainInventory* parent, S32 x, S32 y);
+    static bool handleDragAndDrop(LLPanelMainInventory* parent, S32 x, S32 y);
     static void onParentDraw(LLPanelMainInventory* parent);
 
 private:
@@ -112,6 +114,7 @@ private:
     void updateAutoLabel(LLInventoryPanel* panel);
     std::string computeDisplayLabel(LLInventoryPanel* panel) const;
     LLInventoryPanel* hitTestCustomTab(S32 x, S32 y, S32& tab_local_x, S32& tab_local_y) const;
+    LLInventoryPanel* hitTestAddTab(S32 x, S32 y, S32& tab_local_x, S32& tab_local_y) const;
 
     static std::string getDefaultTabName();
     static std::string sanitizeTabName(std::string name);
diff --git a/indra/newview/llpanelmaininventory.cpp b/indra/newview/llpanelmaininventory.cpp
index 5f37ecdb72..7aced76ff3 100644
--- a/indra/newview/llpanelmaininventory.cpp
+++ b/indra/newview/llpanelmaininventory.cpp
@@ -1371,6 +1371,12 @@ bool LLPanelMainInventory::handleDragAndDrop(S32 x, S32 y, MASK mask, bool drop,
     }
 // [/SL:KB]
 
+    // <FS:TJ> [FIRE-36910] Fix crash when dragging onto the add button for custom inventory tabs
+    if (FSInventoryCustomTabs::handleDragAndDrop(this, x, y))
+    {
+        return true;
+    }
+    // </FS:TJ>
     bool handled = LLPanel::handleDragAndDrop(x, y, mask, drop, cargo_type, cargo_data, accept, tooltip_msg);
 
     return handled;