padding: make sure to polish on completion
this is incredibly important as without polish run we'll not have an implicit size and without that our parents will not know what to do with us. this is doubly problematic when used as a listview delegate (such as via AbstractCard) because the cacheBuffer determines how many delegates to create based on the size of the first delegate right after creation. if we have no size, the listview will create hundreds of delegates, potentially needlessly.