[LyX/master] Do not attempt to mark par break in single-line insets

[Juergen Spitzmueller]

commit 2c0b650aa63fbec4bf2b8093ad3b8391d333e8c9
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Thu Jul 9 18:47:53 2020 +0200

    Do not attempt to mark par break in single-line insets
---
 src/Text.cpp |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/src/Text.cpp b/src/Text.cpp
index 2be5b86..4b897bb 100644
--- a/src/Text.cpp
+++ b/src/Text.cpp
@@ -619,7 +619,8 @@ void Text::readParagraph(Paragraph & par, Lexer & lex,
 		}
 	}
 	// Final change goes to paragraph break:
-	par.setChange(par.size(), change);
+	if (inset().allowMultiPar())
+		par.setChange(par.size(), change);
 
 	// Initialize begin_of_body_ on load; redoParagraph maintains
 	par.setBeginOfBody();