After Ubuntu (MATE) 16.04 it's not possible to sign multiple files with Kleopatra.
All versions from Ubuntu (MATE) [x64] 18.04; 19.10, 20.04 tested by me are affected.
After selecting two or more files, Kleopatra inevitably crashes.
I can only sign one file at a time without Kleopatra crashing.
I use Gpg4win 3.1.11 with Kleopatra, in addition to Linux, also under Windows. There are no problems with the signature of multiple files here.
I use Kleopatra because it is not possible to sign multiple files in GnuPG.
I am now using Ubuntu 20.04. The problem also exists here.
STEPS TO REPRODUCE
1. Copy three files into the download folder to be signed.
2. Open Kleopatra.
3. Click the button: "Sign / encrypt"
4. Open the "Downloads" folder.
5. Select all three Files (CTRL + A)
6. Press the button: "Open"
7. Kleopatra now crashes.
Kleopatra should create several * sig files. Instead, it crashes.
Linux: Ubuntu MATE 20.04 (Tested with a new and fresh installation!)
==> Kleopatra makes handling GPG a lot easier. Thanks for that.
Created attachment 140471 [details]
Screen-Video about this bug
Test on Ubuntu 21.04. I have created a Screen-Video that describes the Problem detailed. After Ubuntu 16.04 LTS - it's not possible to sign multifiles with Kleopatra! No Problems by Kleopatra under Microsoft Windows.