-ms- vendor prefixes not always removed

[sam-ac-dixon]

If you are using an empty browserlist (or >100%) to remove existing vendor prefixes the -ms- prefix is not always removed.

The output is as expected given the following CSS:

.example {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
}

which produces:

.example {
    display: flex;
}

But let's modify the input display property from flex -> none:

.example {
    display: -webkit-box;
    display: -ms-flexbox;
    display: none;
}

The -ms prefix is not removed from the output as you'd expect:

.example {
    display: -ms-flexbox;
    display: none;
}

The expected output is:

.example {
    display: none;
}

[ai]

Removing is not our core feature. If you send a PR, I will help you and release it. But I will not have my own time for this bug.