There is a problem caused by the animations in your web application.
If you type "N", a popup appears, where you can create a new task. This window slides down and the input field gets the focus. This takes around 1 seconds, which should be fine for slow typers. But I'm used to press N and just type right away. The problem is: if you type anything before the input field gets the focus, shortcuts are beeing executed.
If your task title starts with a "N", and you type N (open popup) and N... (task title) too fast, the popup windows moves some more pixel down and the applications remains masked (overlay) after closing the task window, so you have to refresh the website. If you press "F" the fullscreen shortcut gets executed, which is also unwanted, etc.

My proposed solution is not to disable shortcuts while the popup is visible, but to focus the input field right away, so I don't have to wait when I already know what I want to type.