# X-Window XPCE debugger

**URL:** <https://swi-prolog.discourse.group/t/x-window-xpce-debugger/3805>\
**Category:** Help!\
**Tags:** bug\
**Created:** [April 8, 2021, 1:10am UTC](https://swi-prolog.discourse.group/t/x-window-xpce-debugger/3805 "2021-04-08T01:10:15Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\
**Post date:** [April 8, 2021, 6:54am UTC](https://swi-prolog.discourse.group/t/x-window-xpce-debugger/3805/2 "2021-04-08T06:54:16Z")

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Not very nice. It is probably some weird mapping from the FontConfig library specification asking for a fixed font. The way out is to start the editor (?- emacs.) and use the **Edit/Editor preferences** menu to create.edit a config file. Near the end you find  
`display.system_fonts`. There you need to change the `fixed` and `tt fonts`. To what is a bit harder. There is a related discussion on [Config font names, nothing happens](https://swi-prolog.discourse.group/t/config-font-names-nothing-happens/2508)

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