I modified an existing Writer document to contain form control elements like text boxes and check boxes.
Switching “design mode” off everything works fine in LibreOffice (25.2.4.3, Ubuntu 22.04). All the text boxes can be filled in, all the check boxes can be checked and unchecked.
However, exporting this as PDF by “File” → “Export As” → “Export as PDF” activating the option “Create PDF Form” saves a PDF, but while all the text boxes still work perfectly, all the check boxes seem to be numb. Clicking into any of the check boxes just a little red circle appears. Neither clicking nor typing causes any state change of the check box. No check sign appears.
What am I doing wrong? Any further option during Export? Some special setting for check boxes required? Should I try another PDF-Reader instead of the Evince document viewer (42.3)?
Any hint much appreciated
Karl
Maybe try another reader, see Bug 148680 - PDF export: option buttons not working in Linux Document Viewer (xreader/evince) while working in some others
@EarnestAI That’s it.
Using firefox to open the PDF-form allows ticking the check boxes resulting in an x appearing and disappearing when clicking again. Saving from firefox preserves all filled fields and checked boxes. Opening such a saved PDF with evince again does not show the ticked check boxes.
However, using firefox to fill the text fields needs zooming in (ctrl-+) to see what you are writing because the font appears very small.
With qpdfview the behaviour is different as the fields change appearance when clicking into them to fill. In fact the fields become wider and the font bigger. In this appearance also the check boxes can be toggled and a check sign is toggled. However, when clicking outside a form field the appearance of the form fields falls back to the beginning. They shrink, the font shrinks, and the check signs in the check boxes disappear. Nevertheless, when printing from qpdfview everything is there and also the clicked check boxes show a checked sign.
This is all very disturbing. Is this now a fault of libreoffice or evince? A font mismatch between applications? I will study the mentioned Bug to widen my horizon. 
But on a first hand using qpdfview instead of evince is a workaround for me.
Thanks and take care!