Calendar month picker breaks with non-English locales (fix inside)

The plugin is very powerful and flexible, but I ran into a critical issue with the calendar month picker when using a non-English locale (e.g. French).

After an AJAX reload of the calendar, the selected month becomes incorrect (often resets to January). This happens because the JS code parses a localized string like “mai 2026” into a Date object, which is not reliable and breaks outside English environments.

Root cause:
The code relies on parsing the displayed month label instead of using the ISO value already available in the input (e.g. “2026-05”).

Suggested fix:
Use the raw value attribute instead of parsing localized text, for example:

let rawValue = monthpicker.attr('value');
if (rawValue && /^\d{4}-\d{2}$/.test(rawValue)) {
fp.setDate(rawValue + '-01', false, 'Y-m-d');
}

This avoids locale issues and ensures consistent behavior across all languages.

As a temporary workaround, I had to implement a MutationObserver-based fix on the frontend to reapply the correct date after each AJAX reload.

I strongly recommend addressing this in the core plugin, as it affects international users and leads to incorrect calendar navigation.

Otherwise, the plugin remains feature-rich and very useful.