RFR: 8087700: [KeyCombination, Mac] KeyCharacterCombinations behave erratically

[Martin Fox]

On Mon, 14 Aug 2023 16:28:20 GMT, Martin Fox <mfox at openjdk.org> wrote:

> A KeyCharacterCombination should match a key if the target character is printed on that key. For example, the user should be able to invoke the `Shortcut+'+' ` combination by holding down the Shortcut key and pressing a key that has '+' printed on it. This should work even if '+' is a shifted symbol but the user doesn't hold down the Shift key. 
> 
> The Mac implements KeyCharacterCombinations by monitoring keystrokes to discover the relationship between keys and characters. Currently the system only records the character the user typed and no other characters on the same key. This means a shortcut targeting a shifted character may not work until the user types that character using Shift so the system learns the relationship.
> 
> This PR keeps the same mechanism in place but always records the shifted and unshifted character for each keystroke.
> 
> For the Mac the KeyboardTest app was modified to remove tests for characters accessed using Option. We don't look for these characters because under the hood just about every key has some symbol assigned to the Option modifier that the user probably isn't even aware of. For these character we fall back to the existing logic; once the user types the character it will start working as a shortcut.

I created [JDK-8320216](https://bugs.openjdk.org/browse/JDK-8320216) for adding instructions to the test app.

It would be nice to have a non-Latin language in the test so I will look into adding Russian, Arabic, or Hebrew.

I have no idea where to begin with IME-based languages like Japanese and am concerned that the resulting tests would be very platform-specific. In any case that would be an entirely different test app.

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PR Comment: https://git.openjdk.org/jfx/pull/1209#issuecomment-1813575324