The command prompt overrides Ctrl+V in command blocks

When I wanted to paste command into command block, nothing happened because of the prompt overridding pasting commands.
Steps to reproduce

1. Copy ANY command into clipboard
2. Get and open command block
3. Paste the command to it: Nothing happens
4. Write something non-commant into command block
5. Paste the command to it: The command is pasted, but in red