Patch 1.3

Attached the daily check to the initialization on_action instead of game start, for easy initialization in old saves that never ran the framework when it was started.

To initialize on an old save, use the console command:
effect trigger_event = {on_action = on_custom_gui_initialize}

Patch 1.2

Code cleanup; As it turns out, the is_widget_open trigger works perfectly fine in on_actions despite what the paradox wiki states.

Non-existent GUIs are now properly regenerated on a daily basis rather than a monthly basis, with minimal performance overhead.

More advanced save game GUI compatibility. The GUI should now always reload within 1 month of resuming a game, without spamming the player with GUI refreshes.

Added workaround for the issue of GUIs not being retained when reloading a save after a complete game restart.

Will look for a better solution, as the current workaround sometimes recreates the GUIs unnecessarily if you happen to pause the game while playing at speed 5 at exactly the day when the on_action which checks for whether the sidebar UI is loaded.

Minor update: To encourage efficient code, new, smaller lists of indices have been introduced to the dummy characters.
medium_indices: Indices < 1000
small_indices: Indices < 100
very_small_indices: Indices < 10

The use of the full "indices" list is risky to execute code on due to the performance impact of executing thousands of sguis.