if you press the login button then dropdown navbar-personaltools-tools changes to dropdown navbar-personaltools-tools open and the border slightly enlarges from 34x27 to 35x27 which makes the search input to move to the left.
Chrome 34.0.1850.0, Chameleon 1.0.1-dev (464a17d), MW 1.25.
Version: unspecified
Severity: normal