Debugger suspend unexpectedly when debugging.

Reproduction steps:
1. Create a Qt Quick application(symbian component)
2. Set Desktop Qt 4.7.3 for GCC (Qt SDK) Debug mode.
3. add the following code in main.qml
Rectangle
{
id:rect
anchors.left: parent.left
height:100
width: 100
color:"lightgray"
MouseArea
{
anchors.fill: parent
onClicked:

}
}
4. Set breakpoint at line35, See debug.png.
5. Go to the definition of PageStack. Set breakpoint at the begining of
initPage function in PageStack.js.
6. Start debugging and click the lightgray rectangle.
7. When debugger stop at the first breakpoint, press F5.
8. When debugger stop at the second breakpoint, press F10.
9. wait about 5s. Debugger suspend unexpectedly and can not find where
the debugger stop. The file automatically turn back to main.qml.