It happens regularly that I help people with WPML websites, and come across multiple menus with each dozens or even hunderds of items.
At the moment the only sync options are:
1. check all
2. check all manually what you want to sync
3. check all and uncheck manually what you do not want to sync
It would be great to have the following features:
1. In WP Menus Sync, a checkbox next to the menu title of each menu. This checkbox checks/unchecks all items in that menu.
2. In WP Menus Sync, a checkbox for each language. So you can select to sync only one language.
Thank you for taking the time to submit your feature request. I have escalated your request to our 2nd tier support for further review and consideration. I will update you as soon as I have an update to share.