You have probablye set the questionnaire to start in the screenreader mode.
Assemble Questionnaire -> Settings
In screenreader mode, visualization is reduced to a minimum, so that screenreaders can better read the page. This option if for surveys with visually impaired respondents. Please note that a screenreader user can always switch to this mode (if you did not explicitly disable the mode), usually it is not necessary to start the questionnaire in this mode.