In LXLE 16.04.2 pressing Ctrl+Alt+Del will get you this error:
because lxpanel is not installed in this release by default. So to solve this and if you wanna use lxtask you can install it by typing in the terminal: sudo apt-get install lxtask
But if like me you prefer to use htop (already installed by default), go to Main menu--> Settings--> Obkey, look for the Ctrl+Alt+Delete entry and in "command" change "lxtask" for "uxterm -title 'Task Manager' -geometry -0+24 +sb -e htop" (without quotations). Click the save icon and it's done, after you restart or at least logout when you press Ctrl+Alt+Del it will open htop.
You never use Ctrl+Alt+Delete? Clearly you haven't been a Windows user for a very long time! :D Someone who's been a longer term/recent Windows user knows he always has to be ready for a Ctrl+Alt+Del, that crap is always hanging and crashing and freezing! And running things on the background you never executed or have any idea at all of what they are and where they came from...
So old habits die hard, often when I wanna check what's running I just do Ctrl+Alt+Del. And then I remember that all I have to do in LXLE is move the mouse cursor to the button right corner (I moved the bar downstairs) and... click!
I haven't been a 'windows' user in 15yrs or so and even then I think I was on it full time for about 2 years as I was formerly a Mac user before. That isn't to say I haven't 'fixed' a shitload of them but you can't really fix em, per say.
I often tell people I haven't run a 'virus scan' in more than a decade. It's also why I state often that LXLE does not cater to former windows user... how can it... i barely used the damn thing... lol