I have a dock, but it doesn't always remember to reserve edge of screen.  My dock is at the bottom above the taskbar.  I enable "Reserved edge of screen" and it works fine.  Maximized windows stay above the dock.  However I've had windows later not stay above the dock.  It seems to happen after removing my laptop from the docking station when the resolution changes.  I also had it happen when using Remote Desktop to another computer.  For RDP, the other computer was the same resolution.  The workaround is to disable Reserve Edge and reenable it.