Compile without deprecated method against qt5.15.
AdjustToMinimumContentsLength is deprecated see "AdjustToMinimumContentsLength Q_DECL_ENUMERATOR_DEPRECATED_X( "Use AdjustToContents or AdjustToContentsOnFirstShow"), // ### Qt 6: remove In code we just add one element in this combobox:
" ui.m_providerCombo->setVisible(false); ui.m_providerCombo->addItem(i18n("All Providers")); " => QComboBox::AdjustToContents is ok.