With P3Dv3, Adobe Scaleform is being used for user interfaces like menus, ATC Window, and Simconnect created menus by other apps like GSX, ProATC X etc.
However on high DPI displays, e.g. 4k on Win10, the fonts on the ATC / GSX windows are quite small. As part of the P3D SDK, LM has provided the UI files for developers to customize these interfaces. Using those I have created a modified version which shows large fonts.
Instructions:
1. Download and unzip the attached file, you will get MenuWindow.swf.
2. Navigate to Scaleform directory under your P3D installation folder
3. Backup the existing MenuWindow.swf
4. Copy the file from 1 here.
http://www.mediafire.com/download/prtkmma7lt22426/MenuWindow.zip
Note: Tested with P3D v3.2 only