RFR: 8343336: Add persistentScrollBars preference [v6]

[Michael Strauß]

On Wed, 27 Nov 2024 13:09:23 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> Michael Strauß has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains six additional commits since the last revision:
>> 
>>  - Merge branch 'master' into feature/accessibility-hide-scrollbars
>>  - check whether gtk-overlay-scrolling exists
>>  - Merge branch 'master' into feature/accessibility-hide-scrollbars
>>  - add platform keys to javadoc
>>  - Change reducedScrollBars to persistentScrollBars
>>  - Add reducedScrollBars preference
>
> modules/javafx.graphics/src/main/native-glass/gtk/PlatformSupport.cpp line 125:
> 
>> 123:         putBoolean(env, prefs, "GTK.enable_animations", enableAnimations);
>> 124: 
>> 125:         if (g_object_class_find_property(G_OBJECT_GET_CLASS(settings), "gtk-overlay-scrolling")) {
> 
> Looks good, presuming that we want the property to be absent on systems that don't support this setting.

Yes, a property that isn't available shouldn't be included in the preferences map. We've documented that in `Platform.Preferences`:

     * The preferences that are reported by the platform may be dependent on the operating system version
     * and its current configuration, so applications should not assume that a particular preference is
     * always available.

-------------

PR Review Comment: https://git.openjdk.org/jfx/pull/1618#discussion_r1860698822