Multiple window / form application. QFileDialog crashes

[ramzes13]

Dear all,

I am writing a GUI application for image processing. I have three windows (please see attached image):
1. Main GUI.
2. Window for displaying 2D image
3. Window to draw a simple graph
All windows were drawn using Qt Creator 2.0.0 based on Qt 4.7.0 (32bit).

Currently, I am creating windows 2 and 3 inside Main GUI by using new and delete commands.
However, I have a problem: the program crashes sometimes (randomly) when I try to open file using
QFileDialog newdialog(this);
newdialog.setReadOnly(true);
QString path = newdialog.getOpenFileName(this, tr("Open File"), filename);
It is not reproducible, sometimes it crashes on third time of usage, sometimes on fifths. Thus, I cant not understand what is wrong.

Could anybody suggest what is the right way to handle multiple windows/forms?

Thank you for your help,
Roman