The issue is that "load older" was called every time the thread was made
visible, in particular after chat window unfold.
The load more button will naturally be visible when first loading a
thread, it only makes sense to check its final visibility and not
intermediate steps.
But there was a bug where the loading mechanism was relying on the
initial "load older" to fetch messages, because the messaging menu
preview was incorrectly setting the thread as already loaded, when it
just fetched the last message.
Moreover, the "last message" displayed in the preview was not correctly
computed, and it could end up being the last "currently fetched" message
and not the last of all messages (when jumping in the past), and it
could also be a non-persistent message.
runbot-35533
closesodoo/odoo#143129
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>
Sébastien Theys
1c7b149aa7