[LyX/master] Try to catch some other cases of inappropriate TOC updating in internal bufers.

[Richard Kimberly Heck]

commit be19fdee3aa5154eae8b9757daeb2f97bb53bf92
Author: Richard Kimberly Heck <rikiheck at lyx.org>
Date:   Thu Jan 14 14:20:55 2021 -0500

    Try to catch some other cases of inappropriate TOC updating in internal bufers.
---
 src/TocBackend.cpp |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/src/TocBackend.cpp b/src/TocBackend.cpp
index d9ed957..90e7675 100644
--- a/src/TocBackend.cpp
+++ b/src/TocBackend.cpp
@@ -155,6 +155,9 @@ TocBuilder & TocBackend::builder(string const & type)
 // all TOCs.
 bool TocBackend::updateItem(DocIterator const & dit_in) const
 {
+	if (dit_in.buffer() && dit_in.buffer()->isInternal())
+		return false;
+
 	// we need a text
 	DocIterator dit = dit_in.getInnerText();