SpellCheck with CustomDictionaries stopped working

[Krudonix]

Description

Hi,

SpellCheck with CustomDictionaries stopped working after an update in windows 11.

Issue also posted here https://stackoverflow.com/questions/77258504/wpf-spellcheck-on-windows-11-systems

Many thanks,

Reproduction Steps

Create WPF app. With abcd added to the Custom.lex

<TextBox SpellCheck.IsEnabled="True" Text="abcd abcd">
     <SpellCheck.CustomDictionaries>
         <sys:Uri>pack://application:,,,/Custom.lex</sys:Uri>
     </SpellCheck.CustomDictionaries>
</TextBox>

Expected behavior

abcd to not be highlighted as a spelling error

Actual behavior

abcd being incorrectly highlighted

Regression?

This worked in a previous version of windows 11.

Definitely an issue on version 23H2 22631.4037 Seems to work on an old dev machine with 22H2 22621.1265

Not sure at exactly which version this stopped working.

Known Workarounds

No response

Impact

No response

Configuration

Not working on net472 and net8

Other information

No response

[lindexi]

@Krudonix Could you update your project code? I'm afraid it's pack://application:,,,/Custom.lex's problem.

[Krudonix]

Even if I use SpellCheck.CustomDictionaries.Add(uri) to a hardcoded location it still doesn't work.

[Micsupreeme]

Can confirm still unfortunately not working on Core 3.1 (WPF 3.1)

[Krudonix]

Hi,

This is starting to hugely affect us, with more and more clients moving to windows 11.

I don't believe this is a WPF issue but an issue with windows as noted in here

If you have any way to escalate this issue with windows that would be highly appreciated.

Or any potential work around.

We have noticed we can edit the %AppData%\Microsoft\Spelling\neutral\default.dic but not sure how safe this is for us to do.

Many thanks,