My solution for copying block:

Qt Code:
  1. QTextCursor cursor = textEdit1->textCursor();
  3. textEdit1->copy();
  4. textEdit2->paste();
To copy to clipboard, switch view to plain text mode 

But looks like selected text is not placed in clipboard when textEdit1->copy() occurs.
Because the next call pastes old clipboard content to textEdit2.

How to fix the problem? More general question - how to copy QTextFrame or QTextTable from one QTextDocument instance to another?