[Screenview] Cannot select any object in scene view

Unity 2017.4.1.11f1

Unable to select any gameobject by clicking or dragging it in scene view.

Can reproduce this issue by
1. create an empty project.
2. create a cube gameobject and can't click or drag to select it while click it in hierarchy and ctrl+a can.

Same issue doesn't happen in unity 4.6.4f1 in the same PC.

--update
In other test scenes, click(or drag) to select works on some parts of the scene gameobjects( some sprites and particles while others like a new created cube still doesn't work)

--Fixed
Turns out that it's just a Unity function that I didn't notice rather than a bug issue...
Simply turn off lock status of layers(at the top right corner of unity) and problem solved.

 

So, I am not familiar with the internal mechanism of unity sceneview selection...just tried to figure out some differences between these two versions and found this information that I hope could be useful.

I use a test code that simply prints out SceneView.currentDrawingSceneView on every update frame under edit mode(in a function added to EditorApplication.update)

The results in different Unity version are as follows:
-Unity4.6 (in which selection works)
SceneView.currentDrawingSceneView always returns (UnityEditor.SceneView)

-Unity2017(in which selection doesn't work)
when mouse right click or middle click:
SceneView.currentDrawingSceneView returns (UnityEditor.SceneView)
Otherwise(when mouse left click included)
SceneView.currentDrawingSceneView returns Null