AI response — RE: [FLEx] Re: Is it just me, or is FLEx blurry?

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Bart Eenkhoorn

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Sep 9, 2025, 9:16:36 AM (9 days ago) Sep 9

to 'Ken Zook' via FLEx list, B Kh

I asked my assistant for help, and there are some additional things that are worth trying (probably):

You’re right about FLEx not being fully DPI-aware. You can still get much sharper text on Windows 11 with a few OS-level tweaks plus better font choices in FLEx.

Try these in order (stop when it looks good)

1) Force Windows’ sharper per-app scaling for FLEx

Close FLEx.
Go to C:\Program Files\SIL\FieldWorks\Flex.exe (that’s the FLEx executable). Right-click → Properties → Compatibility → Change high DPI settings.
Tick Override high DPI scaling behavior and set the dropdown to System (Enhanced). Click OK → OK, then reopen FLEx.
If “System (Enhanced)” misbehaves, try System. If you choose Application, FLEx won’t be scaled at all—super crisp but probably tiny. (downloads.languagetechnology.org, Quicken, Lenovo Support)

2) Let Windows auto-fix blurry apps + adjust scaling

Settings → System → Display → Advanced scaling settings
• Turn on Let Windows try to fix apps so they’re not blurry.
• If you’re at 150%, try a custom value like 149% or 151% (weird, but it sometimes snaps text into focus). Re-sign in. (Microsoft Learn)

3) Keep all monitors on matching scale

Mixed DPI/refresh between monitors can make one app look soft on one screen. Try using the same Scale (and native resolution) on the monitors you use with FLEx. (Microsoft Learn, eizo.eu)

4) Run the ClearType tuner

Press Win+R → cttune.exe and walk through the wizard. It often helps sub-pixel rendering on certain panels. (Microsoft recommends this alongside scaling changes.) (Microsoft Ondersteuning)

Improve the fonts inside FLEx

In Tools → Configure → Set up Writing Systems, pick screen-hinted fonts for Analysis and Vernacular (e.g., Andika, Charis SIL, Noto Sans), and bump sizes a notch (e.g., 11→12 pt). These families are designed to stay legible at small sizes.
If your writing system allows it, prefer the regular (non-light) weight; light weights look blurrier under scaling.
FLEx on HiDPI is known to be small/awkward; the scaling workarounds above are the current path until the app itself becomes DPI-aware. (SIL Language Software Community)

Advanced (only if you’re still unhappy)

External manifest hack: You can force Windows to treat Flex.exe as DPI-aware by placing an external manifest and enabling the PreferExternalManifest registry flag. This yields razor-sharp text but makes FLEx tiny unless you also use global custom scaling—test carefully and keep a restore point. (Because it’s invasive, I recommend the Compatibility System (Enhanced) route first.) General guidance on per-app DPI workarounds is in Microsoft/Lenovo/EIZO docs. (Microsoft Ondersteuning, Lenovo Support, eizo.eu)

Why this helps

System (Enhanced) uses a better GDI scaling path that often produces sharper text for classic WinForms/GDI apps like FLEx.
Windows’ Fix scaling for apps and custom scaling remove some rounding artifacts at common DPIs (125/150%).
Good hinted fonts + a slightly larger size reduce anti-alias mush.