When you reverse engineer to a model from a MySQL database with for example a single column unique constraint/index and two columns composite unique constraint/index no unique constraint names are generated only indices. So you will only see 3 index icons (and no red U) after the column names and thats why you can’t distinguish between the two different (unique) indices. I also can’t show the index name as a workaround. It look like example 1.
The strange thing is when I first make the model and use unique checkbox in columns tab and use constrains tab to make a composite unique constraint it looks like in example 2.
And when I make a model and only use the constraint tab to make both unique constraints it looks like in example 3.