Some type of scribble lines appear now from V2007

[k0z1]

I noticed that once I upgraded from Visio 2007 to 2013, my previous Visio floor plan drawing documents show a group of scribble lines (somewhat of a group into point or tower) which are not a part of the original document from 2007. There are 2-3 shapes per document that I open. They can not be selected, deleted, modified, or erased. They do appear when printing. (?!)

[JuneTheSecond]

It may be caused by the objects made with Ink Tool pens.
It seems a bug in Visio 2013 when the page is scaled.

One of the solution may be
1. Select All
2. Select ribon Ink Tool Pens
3. Select ribon Convert to Shape 

To confirm the effect please change the zoom ratio slightly.