bug#43865: mml-attach-file could call system file chooser

[積丹尼 Dan Jacobson]

>>>>> "EZ" == Eli Zaretskii <eliz@gnu.org> writes:
>> From: 積丹尼 Dan Jacobson <jidanni@jidanni.org>
>> Cc: 43865@debbugs.gnu.org
>> Date: Thu, 08 Oct 2020 21:22:52 +0800
>> 
>> OK anybody, how can I hack C-c C-a to call the file chooser?

EZ> Click the mouse on the Attachments->Attach File from the menu bar, or
EZ> on the tool-bar button that shows a note with a clip.

But I want to use C-c C-a. I only want to use the mouse when the file
chooser appears. In fact I have the menu-bar and tool-bar both turned
off too.

In fact if there was a way for C-c C-a to be configured to call the
system file choooser, no mouse would be ever needed: TAB TAB TAB etc.
could navigate everywhere. So what we are seeing here is an uncrossable
accessibility canyon due to this little gap!