Docking: Fixed bad ever-growing/ leak (accumulating text into TabsNames forever, fix d38f4dc14 from February 5th, affected docking branch only). (#2109)

imgui_widgets.cpp

@@ -6452,8 +6452,17 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     tab->Window = docked_window;
 
     // Append name with zero-terminator
-    tab->NameOffset = tab_bar->TabsNames.size();
-    tab_bar->TabsNames.append(label, label + strlen(label) + 1);
+    if (tab_bar->Flags & ImGuiTabBarFlags_DockNode)
+    {
+        IM_ASSERT(tab->Window != NULL);
+        tab->NameOffset = -1;
+    }
+    else
+    {
+        IM_ASSERT(tab->Window == NULL);
+        tab->NameOffset = tab_bar->TabsNames.size();
+        tab_bar->TabsNames.append(label, label + strlen(label) + 1); // Append name _with_ the zero-terminator.
+    }
 
     // If we are not reorderable, always reset offset based on submission order.
     // (We already handled layout and sizing using the previous known order, but sizing is not affected by order!)