This bug can be linked to this feature request : http://www.heidisql.com/forum.php?t=20185
I have a mouse with a horizontal scroll wheel but it can not be used. There is a strange behavior, it seems the horizontal scroll is recognized but not used.
cf screenshot attached : move-mouse.png : when the scroll-bar is moved with a mouse-clic
move-scroll.png : the strange scroll-bar that appear when I use the horizontal scroll wheel, but the display window does not move
move-strange.png : another strange behavior, when both scroll-bars are displayed (to reproduce this : use the horizontal scroll wheel and use the mouse pointer to come close to the scroll-bar)
Another horizontal-scroll-wheel bug : when I use this wheel, the normal vertical-scroll-wheel continue to work, but the vertical-scroll-bar does not move anymore untill I click it.