diff --git a/app.py b/app.py
index 24ab722..c73f0a3 100644
--- a/app.py
+++ b/app.py
@@ -54,6 +54,15 @@ if "input_validated" not in st.session_state:
     st.session_state.input_validated = False
 if "template_validated" not in st.session_state:
     st.session_state.template_validated = False
+# Caches für Validierung/Parsing – nur bei Dateiwechsel neu ausführen
+if "last_input_file" not in st.session_state:
+    st.session_state.last_input_file = None
+if "last_template_file" not in st.session_state:
+    st.session_state.last_template_file = None
+if "cached_val_result" not in st.session_state:
+    st.session_state.cached_val_result = None
+if "cached_tpl_result" not in st.session_state:
+    st.session_state.cached_tpl_result = None
 
 # --- Layout: zwei Spalten ---
 col1, col2 = st.columns(2)
@@ -73,9 +82,30 @@ with col1:
 
     if selected_input:
         input_path = Path(app_config.input_dir) / selected_input
-        # Validiere und parse sofort
-        with st.spinner("Validiere Input-Datei…"):
-            val_result = validate_input_file(input_path, app_config.input_schema, app_config.month_sheet_pattern)
+
+        # Nur validieren/parsen wenn sich die Datei geändert hat
+        if selected_input != st.session_state.last_input_file:
+            with st.spinner("Validiere Input-Datei…"):
+                val_result = validate_input_file(input_path, app_config.input_schema, app_config.month_sheet_pattern)
+
+            if val_result.is_valid:
+                records = parse_input_file(
+                    input_path,
+                    app_config.input_schema,
+                    app_config.month_sheet_pattern,
+                    app_config.skip_empty_name,
+                    app_config.skip_empty_antragsnummer,
+                )
+                st.session_state.parsed_records = records
+                st.session_state.input_validated = True
+            else:
+                st.session_state.parsed_records = []
+                st.session_state.input_validated = False
+
+            st.session_state.cached_val_result = val_result
+            st.session_state.last_input_file = selected_input
+        else:
+            val_result = st.session_state.cached_val_result
 
         if not val_result.is_valid:
             st.markdown(
@@ -100,27 +130,19 @@ with col1:
                 for warn in val_result.warnings:
                     st.warning(warn)
 
-            # Parse die Datei
-            records = parse_input_file(
-                input_path,
-                app_config.input_schema,
-                app_config.month_sheet_pattern,
-                app_config.skip_empty_name,
-                app_config.skip_empty_antragsnummer,
-            )
-            st.session_state.parsed_records = records
-            st.session_state.input_validated = True
-
-            # Zeige Zusammenfassung
+            # Zeige Zusammenfassung aus gecachten Records
+            records = st.session_state.parsed_records
             employees = get_unique_employees(records)
             antragsnummern = get_unique_antragsnummern(records)
 
             st.success(f"✅ {len(records)} Einträge in {val_result.info.get('sheets_with_data', 0)} Monats-Sheets")
-            st.metric("Mitarbeiter", len(employees))
-            st.metric("Antragsnummern", len(antragsnummern))
-            with st.expander("Antragsnummern anzeigen"):
-                for an in antragsnummern:
-                    st.text(f"• {an}")
+            pills = " ".join(
+                f'<span style="display:inline-block; background:#e8f0fe; color:#1a73e8; '
+                f'border-radius:16px; padding:4px 12px; margin:3px; font-size:0.9em; '
+                f'white-space:nowrap">{an}</span>'
+                for an in antragsnummern
+            )
+            st.markdown(f"**Antragsnummern:**<br>{pills}", unsafe_allow_html=True)
 
 with col2:
     st.subheader("2. Template")
@@ -140,9 +162,16 @@ with col2:
         )
 
     if selected_template:
-        template_path = Path(app_config.template_dir) / selected_template
-        with st.spinner("Validiere Template…"):
-            tpl_result = validate_template(template_path, app_config.output_mapping)
+        # Nur validieren wenn sich das Template geändert hat
+        if selected_template != st.session_state.last_template_file:
+            template_path = Path(app_config.template_dir) / selected_template
+            with st.spinner("Validiere Template…"):
+                tpl_result = validate_template(template_path, app_config.output_mapping)
+            st.session_state.cached_tpl_result = tpl_result
+            st.session_state.last_template_file = selected_template
+            st.session_state.template_validated = tpl_result.is_valid
+        else:
+            tpl_result = st.session_state.cached_tpl_result
 
         if not tpl_result.is_valid:
             st.markdown(
@@ -176,11 +205,32 @@ st.subheader("3. Mitarbeiter auswählen")
 
 if st.session_state.input_validated and st.session_state.parsed_records:
     employees = get_unique_employees(st.session_state.parsed_records)
-    selected_employees = st.multiselect(
-        f"{len(employees)} Mitarbeiter gefunden – wähle aus, für wen Tätigkeitsnachweise erstellt werden sollen:",
-        options=employees,
-        default=employees,
+    st.caption(f"{len(employees)} Mitarbeiter gefunden – wähle aus, für wen Tätigkeitsnachweise erstellt werden sollen:")
+
+    # "Alle" / "Keine" Buttons
+    btn_col1, btn_col2 = st.columns(2)
+    if btn_col1.button("☑ Alle auswählen", use_container_width=True):
+        for emp in employees:
+            st.session_state[f"sel_{emp}"] = True
+    if btn_col2.button("☐ Keine auswählen", use_container_width=True):
+        for emp in employees:
+            st.session_state[f"sel_{emp}"] = False
+
+    # Mitarbeiter-Liste mit Rahmen
+    st.markdown(
+        '<div style="border:1px solid #d5d5d5; border-radius:6px; padding:8px 12px; '
+        'background:#fafafa; max-height:300px; overflow-y:auto">',
+        unsafe_allow_html=True,
     )
+    selected_employees = []
+    for emp in employees:
+        key = f"sel_{emp}"
+        if key not in st.session_state:
+            st.session_state[key] = True
+        if st.checkbox(emp, value=st.session_state[key], key=key):
+            selected_employees.append(emp)
+    st.markdown("</div>", unsafe_allow_html=True)
+
     st.caption(f"{len(selected_employees)} von {len(employees)} Mitarbeitern ausgewählt")
 else:
     selected_employees = []