macOS: hover does not work when window is inactive

Reproduction

1. Launch a Qt application (e.g. Qt Creator)
2. Click into another window
3. Without clicking, hover the mouse pointer over the Qt application

Expected behavior

Elements with hover effects show the desired hover effects.

Actual behavior

No hover effects are triggered until the user clicks into the Qt application again.

Why this is important for good UX

• Users are used to hover effects working when the application is inactive.
  • Examples of applications where hover effects still work:
    • Apple Maps
    • macOS Notes app
    • macOS Calendar app
    • CLion
• The application feels "dead" and "lifeless" when hover events don't work.
• On multi monitor setups it's easy to forget which application is focused. Then it's confusing when hover events don't work.
• Platform consistency: On Windows, hover events work fine for Qt applications.