Preferences: lazy loading on connect, on by default

Off reads the whole app from app.sab when connecting. Read at each connect, so a
change takes effect on the next one.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app_state.py

@@ -8,7 +8,7 @@ so later rebinding would only ever be seen by the module that did it.
 import configparser
 import os
 
-VERSION = "0.0.0.170"
+VERSION = "0.0.0.171"
 PROPERTIES_FILE = os.path.join(os.path.dirname(os.path.abspath(__file__)), "editor.properties")
 DEFAULT_GRID_SIZE = 10
 DEFAULT_ADD_TIMESTAMP = True
@@ -118,6 +118,7 @@ def load_preferences():
     left_pane_width = DEFAULT_LEFT_PANE_WIDTH
     sedona_home = ""
     trace_dasp = False
+    lazy_loading = True
 
     if os.path.exists(PROPERTIES_FILE):
         try:
@@ -130,6 +131,7 @@ def load_preferences():
             )
             sedona_home = config.get("Editor", "sedona.home", fallback="").strip()
             trace_dasp = config.getboolean("Editor", "trace_dasp", fallback=False)
+            lazy_loading = config.getboolean("Editor", "lazy_loading", fallback=True)
         except Exception:
             pass
     else:
@@ -150,7 +152,8 @@ def load_preferences():
     left_pane_width = max(
         MIN_ALLOWED_LEFT_PANE_WIDTH, min(MAX_ALLOWED_LEFT_PANE_WIDTH, left_pane_width)
     )
-    return sedona_home, grid_size, add_timestamp, box_width, left_pane_width, trace_dasp
+    return (sedona_home, grid_size, add_timestamp, box_width, left_pane_width, trace_dasp,
+            lazy_loading)
 
 
 def save_preferences():
@@ -170,6 +173,7 @@ def save_preferences():
         "box_width": str(BOX_WIDTH),
         "left_pane_width": str(LEFT_PANE_WIDTH),
         "trace_dasp": str(TRACE_DASP),
+        "lazy_loading": str(LAZY_LOADING),
     }
     with open(PROPERTIES_FILE, "w") as configfile:
         config.write(configfile)
@@ -259,5 +263,8 @@ def base_window_title_live():
     return f"Sedona Live Editor [v{VERSION}] — {device_host}:{device_port}"
 
 
-SEDONA_HOME, GRID_SIZE, ADD_TIMESTAMP, BOX_WIDTH, LEFT_PANE_WIDTH, TRACE_DASP = load_preferences()
+# LAZY_LOADING: on connect, read components as folders are opened (True) or the whole
+# app from app.sab first (False). Read at each connect, so a change takes effect on the next.
+(SEDONA_HOME, GRID_SIZE, ADD_TIMESTAMP, BOX_WIDTH, LEFT_PANE_WIDTH, TRACE_DASP,
+ LAZY_LOADING) = load_preferences()
 LAST_PALETTE_KIT = load_last_palette_kit()

device_session.py

@@ -70,11 +70,14 @@ class DeviceSession:
         self._load_slot_registry(parts)
 
         self.sox_client.load(0)
-        try:
-            count = self.seed_from_sab()
-            self.seed_info = f"app read from app.sab: {count} components"
-        except Exception as e:
-            self.seed_info = f"app.sab not used: {e}"
+        if app_state.LAZY_LOADING:
+            self.seed_info = "lazy loading"
+        else:
+            try:
+                count = self.seed_from_sab()
+                self.seed_info = f"app read from app.sab: {count} components"
+            except Exception as e:
+                self.seed_info = f"app.sab not used: {e}"
 
         root_comp = self.sox_client.cache_get(0)
         if root_comp and root_comp.children:

main.py

@@ -2699,6 +2699,18 @@ def open_preferences_dialog():
     )
     chk_trace_dasp.grid(row=5, column=1, sticky="w", pady=(0, 15))
 
+    lbl_lazy = ttk.Label(frame_padded, text="Lazy loading on connect?", anchor="w")
+    lbl_lazy.grid(row=6, column=0, sticky="w", pady=(0, 15), padx=(0, 10))
+
+    # Off: the whole app is read from app.sab when connecting. Takes effect on the next.
+    var_lazy_loading = tk.BooleanVar(value=app_state.LAZY_LOADING)
+    chk_lazy_loading = ttk.Checkbutton(
+        frame_padded,
+        text="Yes",
+        variable=var_lazy_loading
+    )
+    chk_lazy_loading.grid(row=6, column=1, sticky="w", pady=(0, 15))
+
     def apply_preferences():
         try:
             val = int(entry_grid.get().strip())
@@ -2755,6 +2767,7 @@ def open_preferences_dialog():
             app_state.GRID_SIZE = val
             app_state.ADD_TIMESTAMP = var_timestamp.get()
             app_state.TRACE_DASP = var_trace_dasp.get()
+            app_state.LAZY_LOADING = var_lazy_loading.get()
             app_state.SEDONA_HOME = entry_home.get().strip()
 
             app_state.save_preferences()
@@ -2773,7 +2786,7 @@ def open_preferences_dialog():
             messagebox.showerror("Invalid Input", message, parent=dialog)
 
     btn_save_pref = ttk.Button(frame_padded, text="Apply Changes", command=apply_preferences)
-    btn_save_pref.grid(row=6, column=1, sticky="e")
+    btn_save_pref.grid(row=7, column=1, sticky="e")
 
     if not app_state.SEDONA_HOME:
         entry_home.focus_set()