This is a really annoying issue I have. When you copy text, from outside of the dota 2 client, and then go to paste it in a chat room, party, game, lobby etc, instead of pasting what you just copied, it appears to paste your previous copy from your clipboard.

And only way to copy what you want is to paste it, delete, go back and copy the text again and then it will paste. It is hugely annoying. Other relevant points;

1) My copy + paste in windows is fine.
2) Copy + paste on Steam is fine
3) Copy + paste WITHIN the dota 2 client is fine (eg, you copy text from in the game somewhere and paste it in the game somewhere)

Dota 2 pastes your previous copy from your clipboard when copying from outside the dota 2 client.

1) Open up Notepad. Type some words out etc.
2) Select some text, and copy it.
3) Go to Dota 2, and paste into a channel, party, lobby, game anywhere you can type something.

The pasted text will not be what you copied, and instead be your previous copy of your clipboard.

The text you copied should be the text that is pasted.

4) Go back to notepad and copy the same line of text again.
5) Paste into Dota 2 again.
6) It will now be the correct text.