<AWT Dev> [8] Request for review: JDK-8016555: Regression: Focus issues with Oracle WebCenter Capture applet

Anthony Petrov anthony.petrov at oracle.com
Wed Jun 19 05:17:44 PDT 2013

The fix looks fine to me, too.

best regards,

On 06/14/2013 04:41 PM, Anton V. Tarasov wrote:
> Thank you for the review.
> On 14.06.2013 16:17, Leonid Romanov wrote:
>> Looks good then.
>> On 6/14/2013 16:10, Anton V. Tarasov wrote:
>>> It's Ok because the check actually should be correct for any type of
>>> toplevels.
>>> Thanks,
>>> Anton.
>>> On 14.06.2013 10:54, Leonid Romanov wrote:
>>>> Hi,
>>>> The check you've added also affects lightweight frames (because of
>>>> line 382). Is it OK?
>>>> On 6/13/2013 6:52 PM, Anton V. Tarasov wrote:
>>>>> Hello,
>>>>> Please, review the fix.
>>>>> jira: https://jbs.oracle.com/bugs/browse/JDK-8016555
>>>>> webrev: http://cr.openjdk.java.net/~ant/JDK-8014821/webrev.0
>>>>> It's reproducible in the applet mode only, on Windows. When an
>>>>> applet is focused and then a new frame pops up, it doesn't get focus.
>>>>> The reason of the focus loss is the following. When a toplevel is
>>>>> shown while another toplevel is focused, native focus messages
>>>>> should be generated strictly in the following order:
>>>>> The case with applet is special due to the EmbeddedFrame is not a
>>>>> toplevel from native platform perspective, the toplevel is the
>>>>> browser window. Moreover, the EmbeddedFrame window belongs to
>>>>> another process, other than the browser's process. It doesn't
>>>>> receive WM_ACTIVATE messages, these messages are generated
>>>>> (synthesized) for it when it should be activated/deactivated as an
>>>>> AWT toplevel. When EmbeddedFrame loses focus it receives
>>>>> WM_KILLFOCUS (which is triggered by the plugin). However, in case
>>>>> when a new frame pops up, the EmbeddedFrame receives WM_KILLFOCUS
>>>>> after the frame receives WM_ACTIVATE(WA_ACTIVE). So the order is
>>>>> not correct. The reason is the specific of IPC: browser -> plugin
>>>>> -> applet (another process).
>>>>> When EmbeddedFrame receives WM_KILLFOCUS it synthesizes
>>>>> WM_ACTIVATE(WA_INACTIVE) for itself. On processing of this message,
>>>>> AwtComponent::SetFocusedWindow() static method is called which
>>>>> resets the native pointer to the focused window. The point is that
>>>>> as the message is received after WM_ACTIVATE(WA_ACTIVE) (which is
>>>>> sent to the new frame), the new focused window is set to NULL.
>>>>> Later, when focus is requested to the frame's default component, it
>>>>> gets rejected because of the null native focused window value.
>>>>> Before the regression, there was a check for opposite toplevel
>>>>> being set focused in processing of WM_KILLFOCUS for EmbeddedFrame.
>>>>> In case the opposite toplevel is already set focused (which means
>>>>> it already received WM_ACTIVATE(WA_ACTIVE)), no
>>>>> WM_ACTIVATE(WA_INACTIVE) message was synthesized. DKFM in that case
>>>>> created a peer WINDOW_LOST_FOCUS event on java level for the
>>>>> toplevel losing focus (EmbeddedFrame in our case). This code was
>>>>> lost in the process of refactoring and I'm simply bring it back.
>>>>> I've tested it manually with the applet provided in the bugreport
>>>>> (with IE and FF).
>>>>> As the fix simply makes the code spot look like it was before the
>>>>> regression, I consider it low risk.
>>>>> Thanks,
>>>>> Anton.
>>>>> P.S.
>>>>> I'm going to push it to 7u40 as well.

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