Update app.py

app.py

@@ -298,6 +298,25 @@ def main():
         help="Choose to upload your own files or use example data"
     )
     
+    # Clear session state when data source changes
+    if 'previous_data_source' not in st.session_state:
+        st.session_state['previous_data_source'] = data_source
+    
+    if st.session_state['previous_data_source'] != data_source:
+        # Data source changed - clear all structure-related session state
+        if 'selections' in st.session_state:
+            del st.session_state['selections']
+        if 'auto_initialized' in st.session_state:
+            del st.session_state['auto_initialized']
+        if 'results' in st.session_state:
+            del st.session_state['results']
+        if 'structure_data' in st.session_state:
+            del st.session_state['structure_data']
+        if 'reference_name' in st.session_state:
+            del st.session_state['reference_name']
+        st.session_state['previous_data_source'] = data_source
+        st.sidebar.info("🔄 Switched data source - session cleared")
+    
     uploaded_files = []
     
     if data_source == "Upload Files":
@@ -429,6 +448,21 @@ def main():
     if 'selections' not in st.session_state:
         st.session_state['selections'] = {}
     
+    # Track current file names to detect if files changed
+    current_file_names = set([s['name'] for s in structure_data])
+    if 'current_files' not in st.session_state:
+        st.session_state['current_files'] = current_file_names
+    
+    # If file set changed, reset auto-initialization
+    if st.session_state['current_files'] != current_file_names:
+        st.session_state['current_files'] = current_file_names
+        if 'auto_initialized' in st.session_state:
+            del st.session_state['auto_initialized']
+        # Clear old selections that don't match current files
+        old_selections = set(st.session_state['selections'].keys())
+        for old_name in old_selections - current_file_names:
+            del st.session_state['selections'][old_name]
+    
     # Auto-initialize selections for all structures (exclude first and last residue)
     if 'auto_initialized' not in st.session_state:
         for struct in structure_data: