this eroor happened yesterday and until now. I don't know why this problem happen.
I have already reinstalled it, but It is same.
Change 3D>Selection Level to "Leaf Level"
When set to Level 1, the root object (for imported objects, this will be the file name) will be selected when you click on any leaf.
NOTE: This setting only applies when you select in the 3D View by mouse click or click and drag for window box selection. It does not apply when selecting in the 3D Objects list window
It is a global setting (applies to all projects opened on the same computer)