Crash in QQmlDebugService

Hello!

I want to create a custom combo box with modal popup. Everything works fine with modal disabled. But with modal crashed: load first time a dynamic user form, works fine, second time the modal popup crashed.

I also run the gallery example (http://doc.qt.io/qt-5/qtquickcontrols2-gallery-example.html) , and crashed several times. Example: open the dialog examples with modal enabled. Open again the drawer crashed. Example 2: disable drawer modal, enter again to dialog crashed.