fix nasty crash when selection anchor pointed to a deleted cell

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@4791 a592a061-630c-0410-9148-cb99ea01b6c8

src/mathed/math_cursor.C

@@ -52,7 +52,7 @@
 #include <algorithm>
 #include <cctype>
 
-#define FILEDEBUG 0
+//#define FILEDEBUG 1
 
 using std::endl;
 using std::min;
@@ -173,7 +173,7 @@ bool MathCursor::openable(MathAtom const & t, bool sel) const
 	if (t->asScriptInset())
 		return false;
 
-	if (sel) {
+	if (!sel) {
 		// we can't move into anything new during selection
 		if (depth() == Anchor_.size())
 			return false;
@@ -339,6 +339,7 @@ void MathCursor::markErase()
 
 void MathCursor::plainInsert(MathAtom const & t)
 {
+	dump("plainInsert");
 	array().insert(pos(), t);
 	++pos();
 }
@@ -436,7 +437,7 @@ void MathCursor::backspace()
 {
 	autocorrect_ = false;
 	if (pos() == 0) {
-		pullArg(false);
+		pullArg();
 		return;
 	}
 
@@ -814,7 +815,7 @@ void MathCursor::popToEnclosingHull()
 }
 
 
-void MathCursor::pullArg(bool goright)
+void MathCursor::pullArg()
 {
 	dump("pullarg");
 	MathArray a = array();
@@ -835,8 +836,7 @@ void MathCursor::pullArg(bool goright)
 	if (popLeft()) {
 		plainErase();
 		array().insert(pos(), a);
-		if (goright)
-			pos() += a.size();
+		Anchor_ = Cursor_;
 	} else {
 		formula()->mutateToText();
 	}

src/mathed/math_cursor.h

@@ -176,8 +176,6 @@ public:
 	/// remove this as soon as LyXFunc::getStatus is "localized"
 	string getLastCode() const { return "mathnormal"; }
 	///
-	void pullArg(bool goright);
-	///
 	bool isInside(MathInset const *) const;
 	///
 	char valign() const;
@@ -266,6 +264,8 @@ public:
 
 
 private:
+	/// injects content of a cell into parent
+	void pullArg();
 	/// moves cursor index one cell to the left
 	bool idxLeft();
 	/// moves cursor index one cell to the right