Display issues with 4k and other high resolution monitors were fixed in versions 2019.14, 2020.8, and 2021.5 of ElumTools. Simply updating to one of these versions, or higher is all that is now required to fix these display issues.
---Original Article, applies to legacy versions only ---
1. Close Revit.
3. Under the Compatibility tab, click on Change high DPI settings.
4. Check the box in High DPI scaling override. In the drop-down menu change it to System (Enhanced).
Important Note: This will fix ElumTools issues but may result in unknown behavior within the rest of Autodesk Revit.