Minor code changes that aren't necessarily bugs

[Thiago Milczarek Sayao]

While going across the source code I have noticed some code that might be incorrect , such as:

- WindowStage.setScene() has a call to requestFocus()

I might be missing something, but I think it does not belong there because the scene is usually set before show(), and while it may be set after the show and even multiple times, why should it requestFocus() ?

Removing it may also fix https://bugs.openjdk.java.net/browse/JDK-8212060. It is already fixed on glass side, but still...

- WindowStage.hadleFocusDisabled() calls requestToFront() and requestFocus() while requestToFront() already calls requestFocus()

- Intellij points me some cleanups such as null checks before instanceof, ifs that can be merged, etc.


Would those kind of PR be welcome, accepted (if correct) ?

Cheers.