Problem: While projecting your laptop with Microsoft PowerPoint using presentation mode, your computer loses it connection to the Projector and the projector may change to an alternate source.

Answer:  This problem only exists with PowerPoint 2013 due to a new default setting.   You can prevent this issue by changing the default setting in PowerPoint, see below for details.

In PowerPoint turn off "Automatically extend display when presenting on a laptop or tablet".

1.  Go to the File menu in PowerPoint and select Options

2.  Select Advanced, scroll down and deselect the option Automatically extend display when presenting on a laptop or tablet

3.  Click OK to save changes