I added some options on the multiple chart widget. I'm not fully satisfied with the result but it'll do the job until I find a better way to make it.
The inversed pairs (USD/EUR) is a good idea. But it need more work than I expected. It's on my todo list.
Last but not least, I updated the "forex pages" like this one: https://www.mataf.net/en/forex/c/eurusd
Below the chart of the pair I added the chart of the two currency indexes. It's a thing I always wanted but never found the time to do (it was a 5 minutes job).