There are two known causes of this issue.
This error will appear if you are using a high-resolution display and have the Windows text size set to a value in excess of 200%. Please reduce the magnification to 200% or below and relaunch CES Selector.
Windows 8.1 and later allows users to select the size of text using a slider but this method can cause some issues with CES Selector.
Rather than using the slider, please select 'Let me choose one scaling level for all my displays' and then choose the required size.