QExtSerialPort 1.1 (or 1.2 don't know) after invoking close() GUI freezes.

Like in the title.
First i invoke close() to close COM port.
After that I emit signal which makes GUI changes look, it works, i see the changes (like different icons on buttons) BUT interface "freezes". QTextEdit window do not actualizes its content and after moving mouse pointer above buttons i can't see highlighting. I have to click button which open some modal window (witch is also frozen) and close it and then interface start to work. If i close app during that strange behavior debug console do not hide and program is running in the background with 40-50% of processor use.

I know that those description is kinda enigmatic but i don't now nothing more. My code is rather big, i can't show it all. If i make comment //close(); function everything works fine except that i COM port isn't closed.

In my another app i also use QextSerialPort and nothing similar is happening. I can close port and work with GUI.

Anybody?

Finnaly found the reason. It was timer running too fast. I stopped it but it still made gui frozen.