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.

The problem occurs on macOS 12 and 13 which is as far back as I can test. Calling charactersByApplyingModifiers modifiers the NSEvent in some way that causes IMEs to malfunction. I've verified that Chinese - Traditional is also affected.

The solution is to use the same Carbon calls that I used in PR #425. I've written the code and will perform some more tests before submitting a PR. I'm not sure if the right approach is to re-open the original bug and rejuvenate this PR or submit a separate bug. The fix for the original bug will need to be re-tested.

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PR Comment: https://git.openjdk.org/jfx/pull/1209#issuecomment-1826911494