I have used LHS docking for the Windows Start toolbar for years, in XP and in Win7-64, and it usually gives no problems. That's probably because it was designed to work that way if a user set it so.
The only times I have seen problems in the Toolbar are generally when a proggy upsets Windows Explorer. If this happens, it is often ineffective to fiddle with the Toolbar properties - the quickest and most effective fix is to restart Windows Explorer.
Right now, my daughter's laptop has a periodically recurring problem with the LHS Toolbar - it keeps shrinking in width and/or refusing to "auto-hide", and I have shown her how to fix it with a restart of Windows Explorer. So far, I have not been able to establish what is causing this recurring problem.