What's the best way to use Sumatra in multi monitors with different DPI scalings?

[WillingAC]

Background: Recently I switched from MacBook Pro back to Windows laptop, and use my favorite Windows PDF reader, Sumatra, again. The Windows 11 Laptop built-in monitor scales DPI to 150%, and keeps the external monitor DPI 100%.
Issue: As long as Sumatra is launched when the built-in monitor is open, it uses 150% scale no matter in which monitor it was launched. Only in "Second Monitor only" monitor mode will Sumatra use the external monitor's DPI.

I know Sumatra cann't adjust DPI scaling when switching between monitors by design now. But how to let Sumatra properly use external monitor's DPI scaling while in "Extend" monitor mode?

[harryxxiang]

Have you managed to find a solution to this issue? The scaling for ui elements on my higher resolution screen with a different dpi makes all the ui elements tiny.

[blsz]

Same. A comparison of the icon and text size of Sumatra vs Windows Explorer:

100% scaled monitor:

150% scaled second monitor:

[kjk]

Multi-monitor support should be better in latest pre-release

If not, let me know (I don't have a setup to test it)

[WillingAC]

I'll test the pre-release out and update on the result.
Thanks for your time!

[MarcG2]

Multi-monitor support should be better in latest pre-release

If not, let me know (I don't have a setup to test it)

I have variable a variable dpi setup where my main monitor is at 100% and my second monitor is at 200%. I'm finding that the bookmarks bar, find box, page numbers, etc are staying at 100%. Meaning that they're absolutely tiny. Is that supposed to be fixed in the newest version?

[blsz]

The icons are scaling in the pre-release version with 150% display scaling. This is an improvement. The text labels and the text in the bookmarks panel are not scaled. Old version on left. Pre-release on right:

[dengxibo]

Please visit https://github.com/dengxibo/sumatrapdf-plus/releases to check. Version 3.7.6 has resolved this issue.

[MarcG2]

Oh I see this is a fork of Sumatra. Thanks for the suggestion.

[GitHubRulesOK]

@MarcG2 try the next SumatraPDF PRE-Release again, only clear feedback will improve the program for everyone so a fresh issue with clear differences can by addressed one at a time.

[MarcG2]

@MarcG2 try the next SumatraPDF PRE-Release again, only clear feedback will improve the program for everyone so a fresh issue with clear differences can by addressed one at a time.

It still hasn't been addressed in the most recent version. I'm pretty sure someone has opened an issue before for the multi DPI size problem. But I'll go ahead create one.

[GitHubRulesOK]

@MarcG2 the change is in the NEXT pre-release so check again SOON

[blsz]

build version 20065, built on 2026-07-10. Icons scale on a second monitor that is scaled to 150%. UI text does not scale.

The top window is the pre-release version:

[GitHubRulesOK]

@blsz TEST with NEXT pre-release (not yet available)
e.g any one AFTER 3.7.20075