Sometimes a new CSS Selector row is added when this shortcut is used.
Manually change the keyboard shortcut for splitting table cells:
This issue occurs as a single keyboard shortcut is assigned to two different workflows. In Dreamweaver 2014, the keyboard shortcut Ctrl+Alt+S is by default assigned to the creation of a new selector in CSS Designer. The same keyboard shortcut was assigned to the splitting of table cells prior to Dreamweaver 2014.
So, when you use Ctrl+Alt+S in Dreamweaver 2014: