[REG 4->5] focusInEvent is lost if window is shown and mouse cursor is inside of this window

When a window changes its state from hidden to shown some widget gets the focus and focusInEvent fired. But if the mouse pointer is on the position where widget appears, the widget gets the focus but focusInEvent isn't fired.

This happens only on Linux (I tested with kwin and mutter window managers and with various settings of focus stealing).

This doesn't happen on Windows. This also doen't happen on Qt 4.

Steps to reproduce:
1) Build and launch the program from the code attached to this bug:
$ mkdir build
$ cd build
$ cmake ..
$ ./focus_qt5

2) This program shows a QTextEdit widget and hides and shows it every second. Also it handles focusInEvent and focusOutEvent and shows the state of the focus:

void FocusWidget::focusInEvent ( QFocusEvent* event )

{ setText("I have a focus"); setReadOnly(true); qDebug() << "FocusWidget Focus in" << event->reason(); }

void FocusWidget::focusOutEvent ( QFocusEvent* event )

{ setText("I don't have a focus"); setReadOnly(false); qDebug() << "FocusWidget Focus out" << event->reason(); }

So it shouldn't be possible to change the QTextEdit widget because when it got focus it does setReadOnly(true);

3. Place the mouse cursor inside the window and wait one cycle (2 seconds). Now the widget has a focus, but it is editable and the "I don't have a focus" is inside it. So focusInEvent was missed.