Changes have been made in Git for this ticket:

Ticket #7264 - Remember last toggle header pref
Also, rename some prefs to be more consistent that they are dimp prefs.

http://git.horde.org/diff.php/imp/config/prefs.php.dist?rt=horde-git&r1=e8e57523d46676c23b96f2cd3bb80a27e3774ac2&r2=a1523d7507574d696e7063ffb0caa61fe4f74a36
http://git.horde.org/diff.php/imp/docs/CHANGES?rt=horde-git&r1=ca1395db821f0af0142929dbe67cd429a2d72652&r2=a1523d7507574d696e7063ffb0caa61fe4f74a36
http://git.horde.org/diff.php/imp/js/DimpBase.js?rt=horde-git&r1=0b1030b45d961840ba46c680cfca52bc6fc69b7e&r2=a1523d7507574d696e7063ffb0caa61fe4f74a36
http://git.horde.org/diff.php/imp/js/src/DimpBase.js?rt=horde-git&r1=0b1030b45d961840ba46c680cfca52bc6fc69b7e&r2=a1523d7507574d696e7063ffb0caa61fe4f74a36
http://git.horde.org/diff.php/imp/lib/DIMP.php?rt=horde-git&r1=e5c2a8fd4c71eb09dfd8cfe193bf082d63e085a9&r2=a1523d7507574d696e7063ffb0caa61fe4f74a36
http://git.horde.org/diff.php/imp/templates/index/index.inc?rt=horde-git&r1=d7f793427c092e67d8e8461caf2f4cd368c9f4bd&r2=a1523d7507574d696e7063ffb0caa61fe4f74a36

Implemented in IMP 5.

I will live with a preference for open/closed (as long as the behavior 
remains consistent - right now the toggle state is kept within limits 
within a session), but I really think that this should be like other 
UI elements of desktop-like programs: it should stay where you left 
it. Like the panels in the groupware apps, like the state of UI 
elements in other programs, if you left it open it should be open, if 
you left it closed it should be closed. I think we should try and 
follow that consistently where we can.

Disagree with this statement - I toggle all the time.  But the real 
reason is I disagree with this statement:
That is not what I want.  I don't want my last toggle view to be 
sticky.  I generally toggle only to see headers for certain messages - 
I don't want fuller header information most of the time because what I 
care about is the preview text.  So when I toggle a header, I don't 
want that toggle to be permanent - I only want the current message to 
be toggled. (I think there is a bug now that doesn't toggle back on 
the next message view, but at least the toggle state isn't carried 
over across sessions).



So thinking about this more, I am back to my original decision: I 
think there should be a preference over whether you want open or 
closed by default and that's it.  No cookie/pref switching on toggle.   
You could add a "Remember last view" option, but that's starting to 
add a bit of complexity.

Is performance really the reason you don't want this to be a regular 
pref? I don't think there are going to be *that* many toggle actions.

I could live with this being a cookie pref, not a "regular" pref.

I agree with Chuck. Though I would consider storing this as a cookie 
sufficient, if we want to spare the Ajax call.

I was suggesting that open/closed should be sticky across messages and 
across sessions. I usually want to stick with the view I had last, 
until I change my mind, in which case I want that one to stick.

Are you asking for this to be set via AJAX call like sorting is?  I 
don't think this makes sense.  Switching between open and close 
shouldn't be sticky between messages or across different sessions.  I 
would agree with an explicit preference of "should the preview headers 
bar default open/close?"

We should have an implicit preference to remember whether message 
headers are expanded or collapsed in the preview pane.