RFR: 8367045: [Linux] Dead keys not working

[Lukasz Kostyra]

On Tue, 30 Sep 2025 18:19:03 GMT, Martin Fox <mfox at openjdk.org> wrote:

> This bug seems to only apply to Linux systems with no input method framework (IMF) configured. If you want to reproduce the original bug on Ubuntu 24.04 you need to go into Settings > System > "Region & Language" > "Manage installed languages" > Language and verify that "Keyboard input method system" is set to "none". If you change this setting you should reboot the system.
> 
> Normally at the end of a dead-key sequence the IMF sends us a "commit" with the composed character followed by a "preedit-end" signal. When no IMF is configured these signals arrive in reverse order. This is not the way any IMF works and is confusing the heuristic we use to determine whether to send a KeyEvent or an InputMethodEvent.
> 
> To insulate ourselves against this signal ordering issue we add a new flag that ensures that if we're in the preedit window when we start filtering an event we stay there until filtering is done.

Looks good, verified on Ubuntu 24.04 with IBus off.

As a side note for other reviewers, disabling IBus according to PR description actually did not (fully) help on my system, I still had to call `ibus exit` in console to fully disable it and get the issue to appear.

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Marked as reviewed by lkostyra (Reviewer).

PR Review: https://git.openjdk.org/jfx/pull/1924#pullrequestreview-3298943823