[regression] pasting long text into QTextDocument kills application the text copied from

1) open large text file (1mb) in any editor (or open it vith file manager's viewer), copy content in clipboard;
2) open qt-program with QTextDocument, rightclick on it (or try to paste via keyboard).
Result: text editor (or, e.g., file manager) closed, clipboard content cleared.
It's ok with small amount of text or with non-QTextDocument paste destination.