Default applications in linux open suse leap 15?

**Description:** Have

open suse leap ~15

!!! Can't open

.kde.discover.desktop

file which located in

/home/etc/Documents/Apps/

in folder by created me. **Problems:** 1) May be I removed something and now any

(AnyApp.desktop)

is could not opened in my linux system. This is my 1'st problem today. 2) Snapshots is not working also. **I Try:** 1) And when I was try opening any

.desktop

file by (double click) it just was opened with libreoffice application

(calc)

but it's impossible. 2) In Settings/Applcations/No any workable associated application. (except for the calc).