AvalonStudio.TextEditor.Document.UndoStack.ThrowIfUndoGroupOpen C# (CSharp) Method

		private void ThrowIfUndoGroupOpen()
		{
			if (undoGroupDepth != 0)
			{
				undoGroupDepth = 0;
				throw new InvalidOperationException("No undo group should be open at this point");
			}
			if (state != StateListen)
			{
				throw new InvalidOperationException("This method cannot be called while an undo operation is being performed");
			}
		}