Created attachment 128181 [details]
Add language dialog close and not let add language

SUMMARY

American English is the default language; when I try to select the language to add the window close and not let me add the language.

STEPS TO REPRODUCE
1. 
2. 
3. 

OBSERVED RESULT

When select the language the button add enable but the window close and not add the language.

EXPECTED RESULT

Select the language, enable button add, push the add button, close the window and install the language.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 18.04 KDE Neon 5.18
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION