RFR: 8280993: [XWayland] Popup is not closed on click outside of area controlled by XWayland

[Sergey Bylokhov]

On Fri, 5 May 2023 12:27:04 GMT, Alexander Zvegintsev <azvegint at openjdk.org> wrote:

> On Linux systems, we rely on XGrabPointer (X11 API) to capture mouse input and dismiss popup menus on mouse clicks outside the popup menu.
> Unfortunately, on Linux systems using the [Wayland](https://wayland.freedesktop.org/) session this only works inside [XWayland(Wayland's X11 server implementation)](https://wayland.freedesktop.org/xserver.html).
> This means if a user clicks on a part of the screen not controlled by XWayland (e.g. window decorations, other non X11 applications) the popup menu will not be hidden.
> 
> As a workaround, we can hide this menu when the parent popup menu window loses focus.
> However, it does have its drawbacks, which should be described in the documentation.The focus does not change when clicking on the header of its own parent window or on non-focusable windows, .e.g., empty space in system dock, so in this case the popup menu is not hidden.
> 
> Third-party applications use a similar approach.
> 
> I also have doubts about the need to change the documentation, as I can't find where it is described that the popup menu should be hidden when clicked outside the menu.
> 
> CSR: https://bugs.openjdk.org/browse/JDK-8307529

src/java.desktop/share/classes/java/awt/PopupMenu.java line 46:

> 44:  * call {@code show} on that {@code PopupMenu}.
> 45:  *
> 46:  * @implNote On Linux systems using Wayland, the popup menu may not be dismissed

I guess the XWayland is affected, but implementation of the toolkit for Wayland will not have this issue?

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PR Review Comment: https://git.openjdk.org/jdk/pull/13830#discussion_r1187986406