No drop-down for filter groups in cocoa MAC picker

[fuzzyweapon]

No extension filter drop-down appears at all in cocoa pickers. This definitely should be possible given browsers are able to invoke native file pickers with drop downs.

I am not putting in a separate issue for the fact that there is no automatic 'all' wildcard option when selecting since it might be a side effect of the above. (note that simply passing null for extensions does allow you to pick any file type)

Found with High Sierra: Version 10.13.4 (17E199) using lwjgl java bindings

[mlabbe]

This is not a Cocoa feature that can be turned on. It should be possible to add a custom drop-down widget to an existing dialog. If someone wants to take this on, start by reading https://github.com/mlabbe/nativefiledialog/blob/master/docs/submitting_pull_requests.md.

[mlabbe]

Closing issue as won't fix there has been no pull request in 18 months. Still open to a PR on the issue.