Workaround Qt bug Combobox dropdown appear behind window

Question

Right now I have a small tool app that runs in the icon tray. When I click on the icon, the app goes into "windowstayontophint" mode. I added a Combo Box on this window. But when I click elsewhere on desktop, and then click the combo box, the drop down window goes to the back of the window. This seems to be a known bug as reported here:

https://bugreports.qt.io/browse/QTBUG-61804

Is there a workaround for this? I am using Qt 5.9.1.

EDIT: Add some code:

This in MainWindow constructor:

Qt::WindowFlags flags = this->windowFlags();
this->setWindowFlags(flags|Qt::WindowStaysOnTopHint);

Then I put a QComboBox in the mainwindow with preloaded items. First time click, the dropdown appears on top as normal. Then I click onn desktop and then back on the mainwindow and combobox. And drop down becomes at the back of mainwindow. CLick on the link above to see what I mean. The bug report also provide screenshot of what is happening.

Answer 1

Nobody want to put an answer, so I answer this myself.

ANSWER: Update to latest Qt.

It did not work for me because I was having trouble updating (noob here). What basically happened was that Selecting "Update" option on Maintenance Tool does not update SDK from 5.9.1 to 5.10.1. It only update certain things like Qt Creator.

I needed to choose "Add or remove Components" and then adding Qt 5.10.1, but only check the MinGW 32bit only. (Uncheck all others otherwise you need them (like android or other)).

Even after that, you also need to manually download CMake (get it from cmake.com) and set it in "Manage Kits" in Qt Creator.