RemoteObjectPickerWindow draws every element

[sabresaurus]

The RemoteObjectPickerWindow draws every element regardless of if its on screen or not. You can potentially have a very large number of object elements in the window which will make the window run very slowly.

To handle this offscreen elements should not be drawn, replaced instead with GUILayout.Space(). This is something which is done in my PlayerPrefsEditor which might be a good reference - see https://github.com/sabresaurus/PlayerPrefsEditor/blob/3d3664f7f4719b2f882f01e2b2ca94ec230a8781/Editor/PlayerPrefsEditor.cs#L299