The in-line annotation font that is displayed never changes from the default, no matter which font is selected for an individual in-line annotation, or configured globally for all in-line annotations.
A further problem therefore is that if a non-unicode font is the default font, then e.g. Greek characters are not displayed.
Steps to Reproduce:
1. Open a PDF document in Okular.
2. Insert an in-line annotation.
3. Type something.
4. Click OK.
5. Right-click in-line annotation --> Properties.
6. Change font to anything (pick something obviously different for testing).
7. Click OK.
1. Change global font in Settings --> Configure Okular --> Annotations --> Inline Note --> Edit
Font stays as default.
Font changes to the one you've selected.
No error messages are displayed.
As mentioned above, potential knock on effect of non-display of non-unicode characters (see https://bugs.kde.org/show_bug.cgi?id=330527).
Correct, poppler doesn't support specifying which font it should use for annotations so it always uses the same. If you annotate a ps file it works, and also changing the font size also works. This will need someone adding that feature to poppler first so do not hold your breath.
Should I file a bug report against Poppler then?
I have similar issue(CJK characters in inline annotations are not rendered), is the bug report in poppler filed?
OK I found the Poppler bug report, just for anyone's convenience.
Bug 65956 – okular does not show non-latin characters in inline notes
A second issue caused by this is that the font used by Okular for Typewriter and Inline note annotations obviously requires less space compared to the substituted font in other readers, such as Adobe Acrobat reader or pdf.online web-app. The result is that text boxes created around on-screen text annotations in Okular is to small for the text inside them when viewed in another viewer.
A way to handle this better in Okular until custom fonts are supported by Poppler is to use a (much) more space consuming font face for annotations in Okular, or to increase the padding arround Typewriter and Inline note annotations in Okular. My testing suggest that today you need to set the font size in Okular to at least '12' (in contrast to default '9') in order to avoid cropping (for longer lines or multi-line annotations) when the font face used by Okular/Poppler is substituted to another default font face and font size in other PDF readers.