Bad performance of rendering objects with many keys in tree mode

In tree mode, an array with many items renders only the first 100 items and allow to "Show more". This makes sure the performane of rendering large arrays is fast. A similar case is an object with many keys. Right now, the editor renders all keys, which can be slow when having a lot of keys (like thousands).

In case of an object with many keys, it would be neat to only render the first 100 keys to keep performance good.