In the absence of a fix for bug #314873 I'm trying a workaround suggested
by federico.

The goal I'm trying to achieve is to use the "Name" text entry to enter a
complete directory path and filename for a "save as" operation. The suggested
workaround is:

  1. Select "save as" in application
  2. C-x to cut filename
  3. Type directory path using auto-completion
  4. C-v to paste filename
  5. Save

When I was trying this I hit Enter after step 3. I was very surprised to
see the directory path I had just carefully typed disappear on me, and
I started typing it over again.

It took me multiple iterations before I realized that the directory was not
being lost but that it was being absorbed into the state of the dialog box,
as (partially) indicated by the contents of the "Save in folder" button.

I think the current behavior is a bug in that although no information is
actually lost, (it's still in the internal state of the dialog), the visible
state change does not reflect the fact that the information is saved. The
visible effect is that a (potentially very long) directory path disappears
while only a single word changes, (which was subtle enough that I missed it
multiple times).

(I think the state change would have been much less confusing if the entire
path had instead been copied somewhere nearby in the dialog. But I also get
the feeling that displaying directory paths in out of mode in current GNOME.)

There's a separate use case of this dialog where the connection between
internal and external dialog state is much more apparent. If the user enters
one portion of the path at a time and presses Enter between each, then the
directory names are copied one at a time from the Name entry to the "save in
folder" button. In this case, I think it's much easier to follow what is going
on.

One solution that would allow for the use case I naturally tried would be
to not move the state out of the Name entry if there is a slash in it.
Perhaps that would feel like too special of a case in the implementation
but it would have the desirable effect of not making carefully-user-created
state (apparently) disappear from the dialog.

Another datapoint in this decision is to note the behavior when selecting
a directory name from the autocompletion drop-down list. In this case, the
behavior is to add the directory name and a / to the text in the Name field,
and _not_ to move any data from visible to internal state.

Other information: