morte deus

i'm new to doom builder and... i previously made a map, the things have shown up. now in a new map i am working on, the things do not show up. what can this be, and how can i make these things appear? ... seems to vague. all the items i put in BEFORE i had changed a flag value appeared. but i thought flags value meant item respawn. i was wrong. can anyone help me or refer me to any kind of information about "things" in general?

left click to select, right click to drag