Event execution order differs between Linux and Windows

Summary

The order of event execution differs between Linux and Windows for mousePressEvent, mouseReleaseEvent, and contextMenuEvent.

Description

Attached is a small qt project that will reproduce the issue. It is just a QPushButton that prints when it receives the above-mentioned events.

Note: On windows I had to #undef main before the main function to get it to compile.

Expected behavior:

The events are processed in the same order on Linux and Windows.

Actual behavior:

When right clicking the widget that appears, on Linux the events will be processed in the following order:

MOUSE DOWN
CONTEXT MENU
MOUSE UP

On Windows the events will be processed in the following order:

MOUSE DOWN
MOUSE UP
CONTEXT MENU

 Environment

Linux:

$ lsb_release -a
No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 16.04.2 LTS
Release:    16.04
Codename:    xenial

Qt Version: 5.9.1 (installed from qt installer)

Windows:

OS: Windows 10

Qt Version: 5.9.1 (installed from qt installer)