Ubuntu 16.04 nautilus search bar frequently opens and flickers without pressing clrl+f

I have installed Ubuntu 16.04 in dell inspiron 3567. When I open Nautilus. for some reason, the search box is opened automatically and if close the search box, it reopens again and again. I have to press escape key continuously to close the same. The same thing happens in google chrome that the navigation bar is selected randomly without any reasons. Also when working in terminal the cursor blinks faster than the normal and if I type any character or if I press esc key then it becomes normal. Can anyone please tell me how to resolve this problem. Thanks..