From 7c8d167f8ea3e641b0ec26f0c40ec33c4045bb68 Mon Sep 17 00:00:00 2001
From: Juergen Spitzmueller <spitz@lyx.org>
Date: Mon, 20 Nov 2017 10:59:09 +0100
Subject: [PATCH] Longtable: only output the caption contents in a caption row.

Fixes: #10791
(cherry picked from commit 538b38f78c76a56bec7e6cec0314d8f4e0f1e415)
---
 src/insets/InsetTabular.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/insets/InsetTabular.cpp b/src/insets/InsetTabular.cpp
index a49c5bf77d..94eed7893e 100644
--- a/src/insets/InsetTabular.cpp
+++ b/src/insets/InsetTabular.cpp
@@ -33,6 +33,7 @@
 #include "DispatchResult.h"
 #include "FuncRequest.h"
 #include "FuncStatus.h"
+#include "InsetIterator.h"
 #include "InsetList.h"
 #include "Language.h"
 #include "LaTeXFeatures.h"
@@ -2652,6 +2653,17 @@ void Tabular::TeXRow(otexstream & os, row_type row,
 				tail.setMacrocontextPositionRecursive(dit);
 				tail.latex(os, newrp);
 			}
+		} else if (ltCaption(row)) {
+			// Inside longtable caption rows, we must only output the caption inset
+			// with its content and omit anything outside of that (see #10791)
+			InsetIterator it = inset_iterator_begin(*const_cast<InsetTableCell *>(inset));
+			InsetIterator i_end = inset_iterator_end(*const_cast<InsetTableCell *>(inset));
+			for (; it != i_end; ++it) {
+				if (it->lyxCode() != CAPTION_CODE)
+					continue;
+				it->latex(os, runparams);
+				break;
+			}
 		} else if (!isPartOfMultiRow(row, c)) {
 			if (!runparams.nice)
 				os.texrow().start(par.id(), 0);