I can click on the grid to select a cell

docs/Keyboard Support.md

@@ -176,12 +176,55 @@ You can use any HTMX attribute in the configuration object:
 - `hx-target` - Target element selector
 - `hx-swap` - Swap strategy (innerHTML, outerHTML, etc.)
 - `hx-vals` - Additional values to send (object)
+- `hx-vals-extra` - Extra values to merge (see below)
 - `hx-headers` - Custom headers (object)
 - `hx-select` - Select specific content from response
 - `hx-confirm` - Confirmation message
 
 All other `hx-*` attributes are supported and will be converted to the appropriate htmx.ajax() parameters.
 
+### Dynamic Values with hx-vals-extra
+
+The `hx-vals-extra` attribute allows adding dynamic values computed at event time, without overwriting the static `hx-vals`.
+
+**Format:**
+```javascript
+{
+  "hx-vals": {"c_id": "command_id"},           // Static values (preserved)
+  "hx-vals-extra": {
+    "dict": {"key": "value"},                  // Additional static values (merged)
+    "js": "functionName"                       // JS function to call (merged)
+  }
+}
+```
+
+**How values are merged:**
+1. `hx-vals` - static values (e.g., `c_id` from Command)
+2. `hx-vals-extra.dict` - additional static values
+3. `hx-vals-extra.js` - function called with `(event, element, combinationStr)`, result merged
+
+**JavaScript function example:**
+```javascript
+function getKeyboardContext(event, element, combination) {
+  return {
+    key: event.key,
+    shift: event.shiftKey,
+    timestamp: Date.now()
+  };
+}
+```
+
+**Configuration example:**
+```javascript
+const combinations = {
+  "Ctrl+S": {
+    "hx-post": "/save",
+    "hx-vals": {"c_id": "save_cmd"},
+    "hx-vals-extra": {"js": "getKeyboardContext"}
+  }
+};
+```
+
 ### Automatic Parameters
 
 The library automatically adds these parameters to every request: