Key changes:
- Single 'listenersAttached' flag tracks if any listeners are attached
- One shared event delegation handler handles all button types (add, config, remove, favorite)
- Stop propagation immediately on button clicks to prevent multiple triggers
- Added e.stopPropagation() calls to prevent event bubbling
- Consolidated event listener logic into single function
- Added safety checks before calling window.functionName
This fixes the issue where one click added multiple indicators (3x MA, 6x HTS, 4x RSI) by preventing duplicate event listener setup.
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