QMainWindow::resize() doesn't work correctly before window is shown on dual monitor setup

When calling resize() on a mainwindow - with a size that should use both screen of your dual monitor setup - before calling window.show() will resize the window such that it fits on a single monitor.

Let me clarify. Suppose you have two monitors, both with 1600x1200 resulotion. Calling mainwindow.resize(2400,1000) before calling mainwindow.show will resize the window as if you'd called mainwindow.resize (1600,1000).

Example code is attached.