Yes Unified is very much a supported and active theme. What I see on your screenshot seems to be Unified in some sort of odd half-desktop/problem-with-post-edit-buttonalf-mobile state. What device is this and what is the width of the display?

I am actually using desktop.

I purposely resize the window to show icon issue. 

zoom in issue is there even I am full screen. As I mentioned, the issue only happened in unified theme.

If you are using a desktop then it knows it is a desktop device. I believe the mobile icons etc., kick in under 600px device width but I can check that. You need to set the user-agent to a mobile device and view it in the size width of that device.

I am puzzled by your image issue however as the code that is being actioned is the same code and is nothing to do with the theme as such – unless there is specific CSS rules defined that might effect it. But I will run some tests to check nothing has been knocked – although we have no other reports of a problem.