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