1. Open the attached "SearchBox" project and "1" scene
2. Type "A" in Hierarchy search box
3. Click on scene view and press Shift+Space to maximize the Scene window (or right click on Scene tab and select "Maximize")
4. Click on scene view and press Shift+Space again to undo maximizing

Actual result: Search box becomes empty and Hierarchy does not show any of searched objects
Expected result: Search box still contains the same search text and Hierarchy shows all of the searched objects

Reproducible with - 2018.1.0a1, 2017.3.0b4, 2017.2.0f3, 2017.1.2p1, 5.6.3p4

Note: When maximizing and unmaximizing Scene view, Hierarchy loses all of its search information, but the Scene view is still gray, thus indicating that the search is still active (happens only when maximizing Scene view)