Fixes bugs of when multiple messages are being edited simultaneously.
Specifically, typeahead is no longer broken, copying messages to clipboard
is less buggy, and resizing is no longer
broken when multiple messages are being edited.
The "Copy" button will only be shown for "View Source"
or "Topic editing only". Also replaced "Copy to clipboard"
with "Copy and close" to make autoclose less surprising.
Fixes#4238.
Previously,
* We displayed "(no topic)" in .message_edit_topic when there was no
topic;this commit changes that to a placeholder.
* We showed the .message_edit_topic_propagate dropdown when the user
cleared .message_edit_topic, despite the fact that one cannot save
or propagate an empty topic. This commit fixes the behavior.
Fixes#1273.
Previously we showed an "Edit" item in the actions popover menu when a user
could edit the content or topic of a message, and nothing otherwise. We now
show "Edit", "Edit Topic", or "View Source" in the popover menu for every
message, depending on the editability of the message, and present an
appropriate version of message_edit_form when the menu item is clicked.
Finishes #1604 and #1761.
Adds "Topic editing only" along with the tooltip explanation to lower right
of message editing box when it's past the message content editing deadline.
This is controlled through the admin tab and a new field in the Realms table.
Notes:
* The admin tab setting takes a value in minutes, whereas the backend stores it
in seconds.
* This setting is unused when allow_message_editing is false.
* There is some generosity in how the limit is enforced. For instance, if the
user sees the hovering edit button, we ensure they have at least 5 seconds to
click it, and if the user gets to the message edit form, we ensure they have
at least 10 seconds to make the edit, by relaxing the limit.
* This commit also includes a countdown timer in the message edit form.
Resolves#903.
This change would allow anyone in the realm to set a topic for a "no topic"
message. As soon as the message topic is set, only the sender can change it again.
(imported from commit 0a91a93b8fd14549965cedc79f45ffd869d82307)
