Bug in system setting. I change my default language to bangla. After that I am not able to add any outher language. When I click on Add languages button nathing show up. I think popup window will get frozen.

SUMMARY
Bug in system setting. I change my default language to Bangla. After that, I am not able to add any other language. When I click on Add languages button nothing show up. I think the popup window will get frozen.

STEPS TO REPRODUCE
1. kubuntu setting > personalization > regional setting > language > add languages > set to bangla
2. kubuntu setting > personalization > regional setting > language > add languages

OBSERVED RESULT
A popup window will come, but not showing properly (very low opacity). The mouse does not work on the popup. I can't add any language

EXPECTED RESULT

SOFTWARE/OS VERSIONS
Windows:
macOS:
Linux/KDE Plasma: Kubuntu 19.04
(available in About System)
KDE Plasma Version: 5.15.4
KDE Frameworks Version: 5.56.0
Qt Version: 5.12.2

Terminal Report

WARNING: viewBackgroundColor is deprecated, use backgroundColor with colorSet: Theme.View instead
WARNING: viewBackgroundColor is deprecated, use backgroundColor with colorSet: Theme.View instead
file:///usr/lib/x86_64-linux-gnu/qt5/qml/org/kde/kirigami.2/Page.qml:282: TypeError: Cannot read property 'globalToolBar' of null
file:///usr/lib/x86_64-linux-gnu/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:48: TypeError: Cannot read property 'height' of null
file:///usr/lib/x86_64-linux-gnu/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:37: TypeError: Cannot read property 'width' of null
WARNING: viewBackgroundColor is deprecated, use backgroundColor with colorSet: Theme.View instead
WARNING: viewBackgroundColor is deprecated, use backgroundColor with colorSet: Theme.View instead
KActivities: Database connection: "kactivities_db_resources_140636919125696_readonly"
    query_only: QVariant(qlonglong, 1)
    journal_mode: QVariant(QString, "wal")
    wal_autocheckpoint: QVariant(qlonglong, 100)
    synchronous: QVariant(qlonglong, 0)
Nothing to load - the client id is empty
Nothing to load - the client id is empty
org.kde.kcoreaddons: Error loading plugin "kcm_translations" "The shared library was not found."
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/usr/bin")
The environment variable QT_PLUGIN_PATH might be not correctly set
"1 instead of 2 arguments to message {The translation file...} supplied before conversion."
file:///usr/lib/x86_64-linux-gnu/qt5/qml/QtQuick/Controls.2/org.kde.desktop/ScrollView.qml:70: TypeError: Value is null and could not be converted to an object
file:///usr/lib/x86_64-linux-gnu/qt5/qml/org/kde/kirigami.2/Page.qml:282: TypeError: Cannot read property 'globalToolBar' of null
file:///usr/lib/x86_64-linux-gnu/qt5/qml/org/kde/kirigami.2/templates/OverlaySheet.qml:187: TypeError: Cannot read property 'ColumnView' of null
KActivitiesStats( 0x5563e0e5ce50 ) ResultModelPrivate::onResultScoreUpdated result added: "kcm:kcm_translations.desktop" score: 27.4021 last: 1559537033 first: 1558332035