RFR: 8280994: [XWayland] Drag and Drop does not work in java -> wayland app direction [v3]

[Prasanta Sadhukhan]

On Fri, 2 Jun 2023 14:11:18 GMT, Alexander Zvegintsev <azvegint at openjdk.org> wrote:

>> This change resolves the issue that drag and drop from a Java application to a native Wayland application (such as gedit) is not possible on Linux.
>> 
>> Our code it quite picky for the drop target, and requires it to be a top level window with the WM_STATE property set, whereas the XWayland server provides dummy windows without this property.
>> So now we make an exclusion for this case.
>> 
>> After the fix it successfully passes previously failed related manual jtreg/conformance tests on Wayland.
>> Other tests are also passed.
>
> Alexander Zvegintsev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   review comments.

src/java.desktop/unix/classes/sun/awt/X11/XDragSourceContextPeer.java line 416:

> 414:         WindowPropertyGetter wpg =
> 415:             new WindowPropertyGetter(window, XDnDConstants.XA_XdndAware, 0, 1,
> 416:                     false, XConstants.AnyPropertyType);

Minor nit: I guess "false" should be aligned below "window"

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

PR Review Comment: https://git.openjdk.org/jdk/pull/14266#discussion_r1217601367