On launching developer tool in chrome cursor changes to round black

I have a problem in chrome. Whenever I launch developer tool in chrome it changes the cursor and closing it returns to the default pointer like cursor.

I am not getting what changes caused it and how can I can revert back?

In Chrome Developer Tools, in the lower right corner click on the gear icon. That will open dev tools settings screen. Uncheck Emulate touch events parameter there and you'll get your normal cursor back.

Update: It seems like newer version of Chrome(at least my 33 beta) hid that option even deeper. From the developer tools show the console by pressing Esc then switch to Emulation tab and then Sensors sub-menu. From there make sure Emulate touch events is unchecked.

Open chrome developer tool ensure that your cursor is on the developer tool page. do ctrl+Shift+M (This is toggle device toolbar. even you can changes ur round cursor to arrow by clicking on toggle device icon present at the top left of dev tool. )