Right-click on a link from QLabel enables Maximize button on Mac OS

Right-click on <a href="example.com">link</a> from some QLabel enables the maximize button of the window.

How to reproduce:

1. Some window has fixed size being set for its geometry. So that window does not have maximize button enabled;
2. There is a QLabel on that window's form, containing <a href="example.com">link</a>;
3. Right-click on this link;
4. Now maximimize button has become available.

There is another issue alongside: if window has its size fixed, it is still possible to double-click the header and this window will get maximised. I guess, I should have created a separate bug-report for this.

Here's a video of such behaviour: https://www.dropbox.com/s/gh7s3kwe2ipj8ku/label-href-geometry.mp4?dl=0

Test application is also attached (label-href-geometry.zip).

This happens only on Mac OS.
I've tested it on Windows - everything works fine there.
I haven't tested it on Linux. Just've tested in on Linux (Fedora + KDE) - works fine.