Place the cursor correctly after undoing an inset dissolution

The cleanup in 11ca1406 was not correct. It is actually not possible to implement recordUndoInset from the undo API, since the cursor may not be at a different level than the text to be saved.

Fixes ticket #9553

src/Cursor.cpp

@@ -2496,14 +2496,7 @@ void Cursor::recordUndo(UndoKind kind) const
 
 void Cursor::recordUndoInset(Inset const * in) const
 {
-	if (!in || in == &inset()) {
+	buffer()->undo().recordUndoInset(*this, in);
-		CursorData c = *this;
-		c.pop_back();
-		buffer()->undo().recordUndo(c, c.pit(), c.pit());
-	} else if (in == nextInset())
-		recordUndo();
-	else
-		LYXERR0("Inset not found, no undo element added.");
 }
 
 

src/Undo.cpp

@@ -587,6 +587,19 @@ void Undo::recordUndo(CursorData const & cur, pit_type from, pit_type to)
 }
 
 
+void Undo::recordUndoInset(CursorData const & cur, Inset const * inset)
+{
+	if (!inset || inset == &cur.inset()) {
+		DocIterator c = cur;
+		c.pop_back();
+		d->recordUndo(ATOMIC_UNDO, c, c.pit(), c.pit(), cur);
+	} else if (inset == cur.nextInset())
+		recordUndo(cur);
+	else
+		LYXERR0("Inset not found, no undo stack added.");
+}
+
+
 void Undo::recordUndoBufferParams(CursorData const & cur)
 {
 	d->recordUndoBufferParams(cur);

src/Undo.h

@@ -102,6 +102,9 @@ public:
 	/// paragraph or cell containing the cursor.
 	void recordUndo(CursorData const & cur, UndoKind kind = ATOMIC_UNDO);
 
+	/// prepare undo for the inset containing the cursor
+	void recordUndoInset(CursorData const & cur, Inset const * inset);
+
 	/// Convenience: record undo for buffer parameters
 	void recordUndoBufferParams(CursorData const & cur);