Investigation of bug #9236 showed that crash to be due to a Paragraph's
holding a dangling pointer to an old and deleted Layout after the
DocumentClass was reset. Since the backtraces look almost identical, it
seems likely that we have the same problem here.
Since this crash seems almost always to involve tables, I looked at the
code in switchBetweenClasses() and found that the Paragraphs that belong
to "hidden" table cells are not seen by the initial recursion using a
ParIterator: It skips right over them. This was confirmed by test code
suggested by Enrico, with results reported in Trac.
The present patch attempts to deal with this problem in the second
recursion, over Insets. When we see an InsetTabular, we call a new
routine that recurses through the cells, looking for hidden ones. If it
finds a hidden one, it then resets the Layout for the cell's Paragraphs
(there should be only one, but we do not make any assumptions) to the
PlainLayout that belongs to the new DocumentClass. This is good enough,
since such cells never have content.
There is extensive discussion of the patch here:
https://www.mail-archive.com/lyx-devel@lists.lyx.org/msg185095.html
Additional testing by Enrico and me confirmed the existence of the
dangling pointer.
This makes virtually impossible copying a separator inset whithout
also copying the end of paragraph. These insets are not supposed to
be directly inserted by users. For example, the parbreak version
represents a LaTeX paragraph break, not a LyX one. So, if it is
possible to copy and paste it by alone, an unsespecting user may be
surprised to see a paragraph break in the output but not on the LyX
screen (because of the lack of indentation, for example).
In this way, it also becomes a LyX par break from a user point of
view, not any more useful than simply introducing a par break by
hitting <return> (except in those cases where it makes a difference,
in which case they are automatically inserted by LyX).
This reverts commit cde8707 and changes "AGUTeX" back to "agutex".
The maintainer has changed "AGUTeX.cls" back to "agutex.cls" and has
confirmed (through private email) that he plans to keep the filename
all lowercase now that he is aware of case-sensitive file systems.
Empty selections can cause confusing behavior for a few reasons:
(1) some functions behave differently depending on whether there is a
selection. If I press delete, nothing happens (where I expect the
character or inset before the cusor to be deleted). If I toggle bold or
emphasize nothing happens (where if there is no selection the entire
word is toggled). There are other LyX functions that depend on whether
there is a selection or not. Further, I wonder if any part of LyX's code
assumes that if there is a selection it is non-empty.
(2) menu options are incorrectly set. For example, the scissors icon.
For remaining empty selection issues, see #9222.
For more information, see:
https://www.mail-archive.com/lyx-devel@lists.lyx.org/msg184758.html
