Thunderbird always asks what app to use when opening attachments
For several weeks now Thunderbird always asks what app to use when opening jpg, doc or docx, or pptx attachments, even when I have selected Photos, Word, or Powerpoint, as appropriate, and checked "Do this automatically for files like this from now on". Strangely, pdf attachments open correctly in Adobe Acrobat without needing to ask every time.
Thunderbird is up to date, v.91.3.0, 32-bit, in Windows 10.
Thanks for any help you can provide.