Dabble has a custom right-click menu which allows you to undo, redo, copy, cut, and paste.
The browser needs permissions from you to paste from the right-click menu. It is a security feature designed to prevent a malicious website from getting at copied passwords you might have copied.
Firefox does not support this yet without advanced configurations. Please use the keyboard shortcut for paste which works without permissions.
To grant Dabble permission to paste content for you in Chrome, the first time you use the paste function from the right-click menu you will be presented with a browser request like this one:
Simply click Allow and from then on, you can paste content.
If you have blocked Dabble from pasting in the past, you can give it permission now by clicking the lock icon in the URL bar and choosing Allow from the menu like shown here: