RFR: 8155030: The Menu Mnemonics are always displayed for GTK LAF [v2]

[Phil Race]

On Wed, 8 May 2024 05:53:38 GMT, Abhishek Kumar <abhiscxk at openjdk.org> wrote:

>> In GTK LAF, the menu mnemonics are always displayed which is different from the native behavior. In native application **(tested with gedit**), the menu mnemonics toggle on press of `ALT` key. Menu mnemonics are hidden initially and then toggles between show/hide on `ALT` press. 
>> Proposed fix is to handle the `ALT` key press for GTK LAF and mimic the native behavior. Fix is similar to the `ALT` key processing in  Windows LAF. Automated test case is added to verify the fix and tested in Ubuntu and Oracle linux.
>> 
>> CI testing is green and link attached in JBS.
>
> Abhishek Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Var moved to local scope

src/java.desktop/share/classes/javax/swing/plaf/synth/SynthLookAndFeel.java line 668:

> 666:         KeyboardFocusManager.getCurrentKeyboardFocusManager().
> 667:             addPropertyChangeListener(_handler);
> 668:         if (UIManager.getLookAndFeel().getName().contains("GTK")) {

This doesn't seem like an ideal way of doing this.
I don't see any precedent for this approach in the Swing implementation.

We need some method that is more about the properties of a L&F rather than keying off name.

Please look around at LookAndFeel and UIDefaults (etc) for a place you could store a property that tells you what to do.
Or perhaps you this "altProcessor" would be the value you retrieve and if it is non-null you install it. 
Or perhaps this should be pushed down to the GTK L&F

I don't know what the right answer is, I just don't think this approach is it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18992#discussion_r1595782003