Suppose you have a preview inset wrapped around some latex that gives a
value to a control sequence, call it \foo. If you put \foo in ERT later
in the text and wrap a preview inset around that, the value of \foo is
not shown until the buffer is reloaded (when *every* preview inset is
re-evaluated). If you change the contents of the initial preview inset,
so that the value of \foo changes, that change is not reflected in the
later use of \foo until the document is reloaded again (and every
preview inset is re-evaluated). Looking at the lyxpreview.tex files in
the temporary directory where LyX does its work, it doesn't look hard to
my c++less eyes to include the child (or dependent) preview items along
with the parent so that they are all updated at the same time, but
unconnected preview insets are left undisturbed.
Two ways come to mind:
1. number all preview insets from 1 from the start of the document.
(Perhaps that is done already?) Right-clicking on a preview inset would
show two items, one giving the number of the inset, the other having a
slot for the number of a parent preview inset. The parent would then
need to be informed of the child's number, and one would need to check
that the parent's number is smaller than the child's, that it occurs
earlier in the document. Insertion of a new preview inset early in the
document would require updating all numbers.
2. alternatively, make preview insets label-able and
cross-reference-able, although in the nature of a preview inset the
labels and references should not be displayed, but be accessible by
right-clicking. LyX already keeps track of parent-child relations among
labels and references. A change to a labelled preview inset would send
not only it to lyxpreview.tex but all preview insets referencing it.
Using labels would avoid the renumbering problem if a new preview inset
is inserted early in the document, although I don't know how you check
that the parent precedes the child in the document.
Andrew
