Remove setBuffer call in Cursor::push.

This is potentially slow. It also should be unnecessary after
some of JMarc's recent commits. See bug #13050.

(cherry picked from commit 66cfc6af3c)

src/Cursor.cpp

@@ -903,7 +903,8 @@ void Cursor::pop()
 void Cursor::push(Inset & inset)
 {
 	push_back(CursorSlice(inset));
-	inset.setBuffer(*buffer());
+	// See bug #13050
+	// inset.setBuffer(*buffer());
 }
 
 

status.24x

@@ -52,6 +52,8 @@ What's new
 - Fix bug where the dialog asking for saving unapplied changes on buffer change
   popped up twice, or sometimes not at all (bug 12954).
 
+- Improve performance when selecting text on less powerful systems (bug 13050).
+
 
 * INTERNALS