Refine custom export row addition in app.py: update logic to use head for selecting rows, ensuring accurate concatenation of selected rows from the merge DataFrame and improving data integrity in the export process.

app.py

@@ -1213,7 +1213,7 @@ with tab2:
                     if 'export_merge' in st.session_state:
                         select_custom_index = st.number_input("Select rows to add (from top)", min_value=0, max_value=len(st.session_state['export_merge']), value=0)
                         if st.button("Add selected to Custom Export"):
-                            st.session_state['export_base'] = pd.concat([st.session_state['export_base'], st.session_state['export_merge'].iloc[select_custom_index]])
+                            st.session_state['export_base'] = pd.concat([st.session_state['export_base'], st.session_state['export_merge'].head(select_custom_index)])
                         st.session_state['export_base'] = st.session_state['export_base'].drop_duplicates()
                         st.session_state['export_base'] = st.session_state['export_base'].reset_index(drop=True)
                 with clear_export: