Fix indicator toggle functionality and add loading feedback

- Fix JSON parsing bug: JavaScript FormData sends indicator list as
  JSON string inside a list, now properly parsed on backend
- Move form event listener setup to _setupIndicatorForm() called from
  addToCharts() so it's always attached regardless of indicator data
- Add immediate visual feedback: popup hides instantly on submit and
  button shows "Updating..." text

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/BrighterTrades.py

@@ -1382,7 +1382,21 @@ class BrighterTrades:
             # Get indicator names - can be a list (from form checkboxes) or JSON string
             indicator_param = params.get('indicator', [])
             if isinstance(indicator_param, list):
-                indicators_to_toggle = indicator_param
+                # Check if it's a list with a single JSON string element (from JavaScript FormData)
+                if len(indicator_param) == 1 and isinstance(indicator_param[0], str):
+                    try:
+                        # Try to parse as JSON array
+                        parsed = json.loads(indicator_param[0])
+                        if isinstance(parsed, list):
+                            indicators_to_toggle = parsed
+                        else:
+                            indicators_to_toggle = indicator_param
+                    except json.JSONDecodeError:
+                        # Not JSON, use as-is (single indicator name)
+                        indicators_to_toggle = indicator_param
+                else:
+                    # Multiple checkbox values from standard form submission
+                    indicators_to_toggle = indicator_param
             elif isinstance(indicator_param, str):
                 # Try to parse as JSON for backwards compatibility
                 try:

src/static/indicators.js

@@ -597,6 +597,9 @@ class Indicators {
             Receives indicator data, creates and stores the indicator
             objects, then inserts the data into the charts.
         */
+        // Always set up the visibility form event handler
+        this._setupIndicatorForm();
+
         if (idata.indicators && Object.keys(idata.indicators).length > 0) {
             this.create_indicators(idata.indicators, charts);
             // Initialize each indicator with the data directly
@@ -610,6 +613,15 @@ class Indicators {
         }
     }
 
+    _setupIndicatorForm(){
+        // Set up the visibility form event handler
+        const form = document.getElementById('indicator-form');
+        if (form && !form._hasSubmitListener) {
+            form.addEventListener('submit', this.handleFormSubmit.bind(this));
+            form._hasSubmitListener = true;  // Prevent duplicate listeners
+        }
+    }
+
 
     init_indicators(data){
         // Loop through all the indicators.
@@ -621,11 +633,6 @@ class Indicators {
             }
             this.i_objs[name].init(data[name]);
         }
-        // Set up the visibility form event handler
-        const form = document.getElementById('indicator-form');
-
-        // Add a submit event listener to the form
-        form.addEventListener('submit', this.handleFormSubmit.bind(this));
     }
 
     // This updates all the indicator data (re-initializes with full dataset)
@@ -899,6 +906,18 @@ class Indicators {
         // Append all selected indicators as a single array-like structure
         formData.append('indicator', JSON.stringify(selectedIndicators));
 
+        // Show loading feedback immediately
+        const submitBtn = form.querySelector('input[type="submit"]');
+        const originalValue = submitBtn.value;
+        submitBtn.value = 'Updating...';
+        submitBtn.disabled = true;
+
+        // Hide the popup and show a brief loading indicator
+        const popup = document.getElementById('indicators');
+        if (popup) {
+            popup.style.display = 'none';
+        }
+
         // Send form data via AJAX (fetch)
         fetch(form.action, {
             method: form.method,
@@ -908,10 +927,15 @@ class Indicators {
                 // Handle success (you can reload the page or update the UI)
                 window.location.reload();
             } else {
+                // Restore button on error
+                submitBtn.value = originalValue;
+                submitBtn.disabled = false;
                 alert('Failed to update indicators.');
             }
         }).catch(error => {
             console.error('Error:', error);
+            submitBtn.value = originalValue;
+            submitBtn.disabled = false;
             alert('An error occurred while updating the indicators.');
         });
     }