Speedbar moves to the right when dragged from the titlebar in any direction.
It happens on Windows 8, run with -Q, with this version:
GNU Emacs 24.4.1 (i686-pc-mingw32)
of 2014-10-24 on LEG570
It does not happen on previous version:
GNU Emacs 24.3.1 (i386-mingw-nt6.2.9200)
of 2013-03-17 on MARVIN