The File Editor is not show in Unity 4.6
They said:
"As this is a bug at Unity’s end, we have to wait for Unity to fix it. According to them, it should work in any version prior to Unity 4.6. It is only the File Editor which does not work in Unity 4.6 … everything else works fine."
BUT is work now with this setting:
"We’ve just heard back from Unity regarding the bug with the File Editor, and they say that it may be a bug with Unity’s Dark colour scheme, and that changing to the Light skin by going to Preferences > Skin (Pro Only) should fix the problem."