Please consider to add another check box option in the preference so users do not need to have this work-around
You want to code assistant to appear when typing and not only when typing . or hitting ctrl/cmd + SPACE. Go to Preferences -> FDT -> Editor -> Code Assist. Set the delay in the "Auto activation Delay:" to 50. In the field "Auto activation triggers for AS:" you insert "abcdefghijklmnopqrstuvwxyz_.:".
See point n. 5 in: