[Users] Keyboard Navigation in Message View

[Dustin Miller]

Linux Mint 20 XFCE (based on Ubuntu 20.04)
Claws Mail (CM) 3.17.6

The following is a list of things that I wish could be changed (in the
code or by a setting) in relation to how the keyboard navigation works
when viewing an email in the message pane of the primary CM interface:

* 1. Pressing the 'Space' key moves you down one screen view (i.e.
  'page'). If you are already at the bottom, it attempts to move you to
  the next unread message in the same folder, and if there are none in
  that folder, it will attempt to move you to an unread message in a
  different folder. I wish that it would do nothing when you are at
  the bottom of the message. (I think this behavior has been present
  for a good number of versions, at least since I started using CM.) (Is
  this a bug? A feature? If a feature, then I will probably file an
  enhancement request for a setting or hidden advanced setting by which
  this could be adjusted.) (FWIW, note that this behavior is
  inconsistent with what happens when you are at the top and press
  'Shift + Space'.)

* 2. Pressing 'Shift + Space' is meant to move you up one screen view
  (i.e. 'page'). If you are already at the top, it attempts to move you
  to the next unread message in the same folder; if there are none in
  that folder, it will NOT attempt to move you to an unread message in a
  different folder. I wish that it would do nothing when you are at the
  top of the message. (I think this behavior has been present for a
  good number of versions, at least since I started using CM.) (Is this
  a bug? A feature? If a feature, then I will probably file an
  enhancement request for a setting or hidden advanced setting by which
  this could be adjusted.) (FWIW, note that this behavior is
  inconsistent with what happens when you are at the bottom and press
  'Space'. See #1.)

* 3. Also, pressing 'Shift + Space' actually causes the action to be
  executed twice; thus, it either moves you up two screen views, or
  else moves you to the top and then tries to go to the next unread
  message. (Pretty sure this one's a bug, and it seems pretty recent;
  perhaps introduced during the process of adding keyboard navigation
  for the LiteHTML viewer?) My expectation is that pressing this once
  would only cause the action to be executed once. (I guess there's a
  slight chance this could be caused by something on my system; can
  anyone else reproduce it?)

I've tested these with several different types of message parts, and the
behavior seems consistent. I haven't tested these for a message that's
opened in a separate window. I've also confirmed that 'Return' and
'Shift + Return' (i.e. for moving up and down by only a line or two) do
not show behavior similar to any of the above issues. I've looked
through 'Configuration / Preferences' and was not able to find a
setting to control this. I'm pretty sure there isn't already a hidden
advanced setting to control this, but I didn't actually confirm it by
reviewing the list to see if anything new had been added.

Let me know if more information is needed for you to understand these
issues.

BTW, a big thanks to the developers for implementing keyboard
navigation for use with the LiteHTML viewer -- that's quite handy to
have. Kudos! :)

Dustin