some fixes

python_app/gui/runtime/history.py

@@ -59,12 +59,18 @@ def remove_last_aligned_histories(
     return retained_raw, retained_preprocessed, retained_results
 
 
-def build_run_history_signature(
+def build_processor_run_signature(
     config: RunConfigModel,
 ) -> tuple[object, ...]:
-    """Build deterministic signature to detect run-settings changes (excluding live processing params)."""
+    """Build signature of settings that change the data SHAPE the data_processor parses.
+
+    Excludes the preprocess set names on purpose: the data_processor does not consume
+    calibration/reference sets (those are applied upstream by the data_preprocessor), so
+    changing a set must NOT restart the processor. Restarting it would also tear down the
+    locator TCP server it hosts and drop every connected client. Only genuine shape changes
+    (radar model, sweep, switch layout, combos) require a processor restart.
+    """
     combos_signature = tuple((int(combo.input), int(combo.output)) for combo in config.combos)
-    preprocess_signature = tuple(preprocess_asset_model(config, key).set_name for key in PREPROCESS_ASSET_KEYS)
     sweep_points_signature: object = "adc" if config.is_kamil_adc else int(config.radar.sweep.points)
     return (
         str(config.radar.model),
@@ -85,11 +91,23 @@ def build_run_history_signature(
         str(config.output_switch.driver),
         int(config.output_switch.positions),
         bool(config.output_switch.invert_logic),
-        preprocess_signature,
         combos_signature,
     )
 
 
+def build_run_history_signature(
+    config: RunConfigModel,
+) -> tuple[object, ...]:
+    """Build full signature for GUI display-history reset (processor shape + preprocess sets).
+
+    Display history still resets when the reference/calibration set changes (the on-screen
+    B-scan would otherwise mix old- and new-reference frames), even though the processor
+    process itself is intentionally kept alive across that change.
+    """
+    preprocess_signature = tuple(preprocess_asset_model(config, key).set_name for key in PREPROCESS_ASSET_KEYS)
+    return build_processor_run_signature(config) + (preprocess_signature,)
+
+
 def _tail_occurrence_key(history: list[THistoryCollection], index: int) -> tuple[int, int]:
     """Return `(collection_id, occurrence_from_tail)` for the item at `index`."""
     collection_id = int(history[index].collection_id)