Reset index of export base after adding new entries in app.py: ensure the DataFrame maintains a clean index by resetting it following the concatenation and duplicate removal process.

app.py

@@ -1087,6 +1087,7 @@ with tab2:
                     if st.button("Add to export"):
                         st.session_state['export_base'] = pd.concat([st.session_state['export_base'], st.session_state['export_merge']])
                         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)
             else:
                 st.error("No portfolio to download")