slovnik is a frameset page, where the input form is in one frame, and the translation
results are in a different frame.  Therefore when you submit the form, the results
frame navigates to a new page, causing content_buffer_location_change_hook to fire,
which in turn causes conkeror to switch to normal_input_mode.  However, the input
field is still focused in that other frame, so conkeror is left in an inconsistent
state.