Fix bug with TentativeUndo where the undo history was being damaged on OS X.

For example the sequence ['a', 'c', left, 'b', undo] would produce "c" instead of "ac".

1 files changed, 2 insertions, 0 deletions

diff --git a/src/Document.cxx b/src/Document.cxx
index 7d34dace1..3f365fdf4 100644
--- a/src/Document.cxx
+++ b/src/Document.cxx
@@ -216,6 +216,8 @@ void Document::SetSavePoint() {
 }
 
 void Document::TentativeUndo() {
+	if (!TentativeActive())
+		return;
 	CheckReadOnly();
 	if (enteredModification == 0) {
 		enteredModification++;