Hi mvg,
thanks for the bug report. To fix this, please go inside PinyinInput::TextEditor and copy the following content into the slot onBackspaceKey:
// Only let the pinyin preview handle the backspace key if enabled and preview is visible
if ( PinyinEnabled && CharacterPreview.Enabled )
TriggerPinyinEvent( '\0', Core::KeyCode.Backspace );
else
handleBackspace();
We will put your feature request with the number layout to our backlog and will think about implementing this at a future release.
Best regards,
Julian