If you are using Dreamweaver CC 2017 on a Windows Hi-DPI machine, and have increased the text size beyond 100%, then some panels in Dreamweaver do not display correctly.
For example, the Preferences (Edit > Preferences) panel does not load any content. Other panels can also appear truncated.
In the Windows Display settings, set the font size to 100%. Close Dreamweaver CC 2017 and launch it again.