Copying, pasting, etc. still insert "c", "v", etc.

The bug

Pasting text with Ctrl+V still inserts the letter "v" in the text box or the chat. The same occurs for Ctrl+C, Ctrl+A, etc.

How to reproduce

1. From another application, copy a string, for example hello.
2. In Minecraft, paste it (in chat or a text box). hellov shows up.