Q:

How can I make keyboard shortcuts register on key release, rather than on key press?

I want to have shortcuts like in Windows; Super opens the start menu, Super+S opens a search window, Super+E opens Thunar, etc.
I know how to set keyboard shortcuts, but when I set Super to open whiskermenu, whiskermenu also pops up in every other instance of Super+* shortcuts. I think this is because XFCE registers the shortcuts as they come, rather than waiting for simultaneous release (like in Windows).
How do I set that up?

A:

You can achieve it this way :
install xbindkeys
sudo apt-get install xbindkeys

Run the command :
xbindkeys --key

In the white box that appears, Press your key combination. Example Win + E will return the following :
"(Scheme function)"
    m:0x50 + c:26
    Mod2+Mod4 + e

Now copy the last (or last second) line and use it as given below
create a new file .xbindkeysrc in your home Directory
touch $HOME/.xbindkeysrc

Open it
nano $HOME/.xbindkeysrc

Enter your required command and keys as given below 
"nautilus"
    release+Mod2+Mod4 + e

(Note : don't forget release , Replace "nautilus" with any command )
Similarly add all the requires command-key combinations one below the other
Now add xbindkeys to xinitrc :
sudo nano /etc/X11/xinit/xinitrc

add xbindkeys to the starting (1st line or before . /etc/X11/Xsession)
Reboot your system and you should get expected behavior
TIP : Make sure you don't set conflicting configurations in xbindkeys and your GUI method provided by your DE 
For more examples , man xbindkeys

