I have to toggle Windows taskbar auto hide/unhide frequently. Is there any way (eg via script, registry or tool) that can let me simply double click to toggle the setting?
Try using Aviassin Taskbar Eliminator.
I heard it is a good one.
You could use the following AutoIT script for showing/hiding the taskbar (or compile it to executable(s) with so you can run this without needing AutoIt)
This example script hides the taskbar, sleeps 3 seconds and shows the taskbar:
Opt('WINTITLEMATCHMODE', 4) ControlHide('classname=Shell_TrayWnd', '', '') Sleep(3000) ControlShow('classname=Shell_TrayWnd', '', '')
The script has been taken from: http://www.autoitscript.com/forum/topic/27505-hide-taskbar/
This answer uses AutoHotkey:
You can set it to whatever key combination you need.
You could just leave it hidden and use instead:
I found something called Taskbar Eliminator via Google that sounds like what you're looking for.
It's no double click as the question requires but it let's you toggle the auto hide by using a hotkey and it lets you decide on you're own choice of hotkey.
I tested it with Windows 7, works for me (and I keep it), maybe this helps s.o. else as well. There is also a Version for Windows 10 but I haven't tested it yet.