Poor Font Rendering in Editor
If your Editor text appears jagged or with uneven weights, you can usually resolve this by enabling or fine-tuning Windows ClearType, as described in this Microsoft support article for XP. Recent versions of Windows have ClearType enabled by default, but the settings may need to be adjusted for your display.
For certain systems, the Windows update 3013455 (MS15-010), released on 10 February 2015, caused degradation of simple fonts such as Courier New, Scrivener's default editor font. Microsoft released patch 3037639 to resolve this issue.