Closing new nonchild window in Qt

Question

i'm trying to make 2 windows. 2nd should be called in 1st. I don't connect them child->parent. But when i called 2nd window and closed it 1st window closed too. What should i do? Both windows are inhereted from QWidget. C++ and Qt Sorry for my poor describe. I have a main window. Class inherited from QMainWindow. That i created 2nd window. Class inherited from QWidget. In first (main window) i'm creating and calling 2nd window ``` ConfigWindow *ConfWindow = new ConfigWindow(); ConfWindow->show(); ``` Without giving link to parent. Everything works fine, but when i close 2nd window (config-window) my main window is closing too. I needn't in this. What should i do to block closing main window after config-window closing. Hope describe a little better. My first window has this flags: ``` this->setWindowFlags(Qt::Tool | Qt::FramelessWindowHint); ``` Without them everything is fine. Could i change something if i need that flags in my window?

Accepted Answer

You need something like:

```
QApplication app(argc, argv);
app.setQuitOnLastWindowClosed(false);
```

Here is the test program: http://pastebin.com/f5903c5f4.

Beware, now you need to explicitly call quit() in the destructor of your main window.

If you read QApplication::quitOnLastWindowClosed documentation, you will find out that:

If this property is true, the applications quits when the last visible primary window (i.e. window with no parent) with the Qt::WA_QuitOnClose attribute set is closed. By default this attribute is set for all widgets except for sub-windows

Because your main window is a (frameless) tool window, it does count. That leaves ConfWindow as the only non sub-windows top-level widget. Thus, if you close ConfWindow, it provokes the application instance to quit.

Closing new nonchild window in Qt

Solution

Problem