davinci resolve png stretch

i am trying to key something to later on import into an after effects project. i intend keying within resolve and puttin a flat green png behind in order to render out with the flat green, which i can get rid of easily in AE. problem is that on the timeline i cannot stretch out the green png. it had worked in another project, doesn't now, though it is the very same png. reloaded the other project. the green png on the timeline can still be stretched, but if i put in the very same png a second time, this new one cannot be stretched. just like in the new project. i must have clicked something that prevents a pic to be manipulated that way and do not know what ...

thnx.
g