bug#24579: [PATCH] borderless windows on OS X

[martin rudalics]

>> We do: Emacs' native tooltip frames with a ‘border-width’ of zero should
>> accomplish precisely that.
>
> I meant the feature to create an arbitrary frame without a border, from 
ELisp.  We don't have this, AFAICT.

What is an arbitrary frame?  A frame without the window manager's title
bar can't be dragged with the mouse.  A frame without an external border
can't be resized with the mouse.

>> The recipes there don't work: The ‘border-width’ parameter is usually
>> ignored by the window manager for "normal" frames and replaced by the
>> standard border.  You have to create a CWOverrideRedirect window - a
>> frame that is _not_ handled by the window manager.
>
> Right.  Do we have a way to do this from ELisp?

Add a (border-width . 0) entry to `tooltip-frame-parameters' and show a
native Emacs tooltip.

martin