RFR: 8155030: The Menu Mnemonics are always displayed for GTK LAF [v3]

[Phil Race]

On Wed, 15 May 2024 18:17:20 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:
> 
>   Alt press property added for GTK L&F

src/java.desktop/share/classes/javax/swing/plaf/synth/SynthGraphicsUtils.java line 677:

> 675:                 // Check to see if the Mnemonic should be rendered in GTK.
> 676:                 if ((UIManager.getLookAndFeel().getName().contains("GTK"))
> 677:                     && SynthLookAndFeel.isMnemonicHidden() == true) {

I was not expecting this check for GTK to still be here.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18992#discussion_r1612092578