An addin for Visio 2013+
If you use layers in Visio, then you will want this.
Download from here
Unzip the contents to a folder, and run the setup.exe.
Enjoy free for 30 days.
Microsoft Visio has a complex layering system that can be confusing.
The appearance of a Visio page can be drasitically altered by changing the visibility and printability of layers.
Effective use of layers can provide multiple views of the same base visual information, reducing the need to copy shapes from one page to another, and thus eliminates mistakes.
Layer Manager makes this simple.