What is the meaning of "Allah's creation of His slaves' actions" and is it one of the issues of predestination (Qadar)?

It is not correct to deny someone's faith due to their ignorance of some of its details. Faith increases and strengthens with knowledge and understanding, but general faith benefits its possessor and removes from him disbelief and iniquity. Sheikh al-Islam Ibn Taymiyyah explained this by stating that whoever believes in Allah and His Messenger, and then dies before knowing the specific laws of the religion, dies as a believer. His faith is not like the faith of one who knew the laws and acted upon them, for the latter's faith is more complete. He also mentioned that a person might be ignorant of matters that have not reached him from the Messenger, and had he known them, he would have believed in them. This does not make him a disbeliever, but rather ignorant. And whoever believes in the Messengers with a general faith, and acts upon what he knows, he is among the awliya' (friends) of Allah. However, he misses out on the perfection of wilayah (sainthood) due to the detailed knowledge he lacked. Both are awliya' of Allah, and Paradise has ranks according to faith and piety.