To always allow pasting in the editor, follow the steps below:
Step 1: Go to Internet Explorer and click 'Tools' (Alt+x) in the top right corner of the browser and when the drop down menu appears, click 'Internet Options'.
Step 2: Under the 'Security' tab, choose 'Internet Zone' and click 'Custom Level'.
Step 3: Scroll down and under Scripting, you will find an option “Allow Programmatic clipboard access”.
Under that click on Enable and click OK and then Apply and OK again.
Pasting will now occur without being prompted.