JDK-8220272: Found the problem + possible fix

[Jason Shattu]

Forgive my ignorance, but I can't work out how to submit an OpenJFX bug 
report.

The link you've sent  ultimately brings you to this page: 
https://bugs.openjdk.java.net/secure/Dashboard.jspa

but I don't see any thing for JavaFX here.

Thanks,
Jason

------ Original Message ------
From: "Nir Lisker" <nlisker at gmail.com>
To: "Thiago Milczarek Sayao" <thiago.sayao at clamed.com.br>
Cc: "openjfx-dev at openjdk.java.net" <openjfx-dev at openjdk.java.net>
Sent: 15/04/2019 10:45:36
Subject: Re: JDK-8220272: Found the problem + possible fix

>Hi Thiago,
>
>Anyone can create a PR on GitHub, see
>https://github.com/javafxports/openjdk-jfx/blob/develop/.github/CONTRIBUTING.md
>.
>
>- Nir
>
>On Mon, Apr 15, 2019 at 3:47 AM Thiago Milczarek Sayao <
>thiago.sayao at clamed.com.br> wrote:
>
>>  * THE PROBLEM *
>>
>>  In GlassApplication.cpp, the GDK_FOCUS_CHANGE event gets called from the
>>  last window to the first on my setup (I suspect "out-of-order" on some
>>  setups and even occasionally in the expected order). So the code to keep
>>  the latest enabled window fails (refering to WindowStage.java
>>  activeWindows) - that's why the "First Window" (on the code to reproduce
>>  the bug report) shows on top - because openjfx thinks it was the latest
>>  window. In WindowStage.java:
>>
>>      final void handleFocusDisabled() {
>>          if (activeWindows.isEmpty()) {
>>              return;
>>          }
>>          WindowStage window = activeWindows.get(activeWindows.size() - 1);
>>  //<-- HERE!!
>>          window.setIconified(false);
>>          window.requestToFront();
>>          window.requestFocus();
>>      }
>>
>>  When there is a WINDOW_MODAL this code gets called because the modal
>>  window disable it's parents (so they do not get events - it's correct). So
>>  openjfx brings up what it thinks it's the latest window - but since the out
>>  of order GDK_FOCUS_CHANGE - it's the wrong window (activeWindows list has
>>  not the correct order).
>>
>>  The Gtk docs states GDK_FOCUS_CHANGE is true "if the window has gained the
>>  keyboard focus" which may not be directly correlated to openjfx's
>>  WindowEvent.FOCUS_GAINED.
>>
>>  * THE FIX *
>>
>>  To fix this, WindowEvent.FOCUS_GAINED must be called in order of which
>>  window is shown (because the window is inserted on activeWindows at this
>>  event).
>>
>>  So I have modified glass_window.cpp to immediately call
>>  WindowEvent.FOCUS_GAINED when showing the window:
>>
>>  void WindowContextBase::set_visible(bool visible) {
>>      if (visible) {
>>          gtk_widget_show_all(gtk_widget);
>>
>>          //JDK-8220272 - fire event first because GDK_FOCUS_CHANGE is not
>>  always in order
>>          if(jwindow && isEnabled()) {
>>              mainEnv->CallVoidMethod(jwindow, jWindowNotifyFocus,
>>  com_sun_glass_events_WindowEvent_FOCUS_GAINED);
>>          }
>>      } else {
>>          gtk_widget_hide(gtk_widget);
>>          if (jview && is_mouse_entered) {
>>              is_mouse_entered = false;
>>              mainEnv->CallVoidMethod(jview, jViewNotifyMouse,
>>                      com_sun_glass_events_MouseEvent_EXIT,
>>                      com_sun_glass_events_MouseEvent_BUTTON_NONE,
>>                      0, 0,
>>                      0, 0,
>>                      0,
>>                      JNI_FALSE,
>>                      JNI_FALSE);
>>              CHECK_JNI_EXCEPTION(mainEnv)
>>          }
>>      }
>>  }
>>
>>  Did some tests and it seems to fix the problem.
>>
>>  I do not have permission to make a PR, so posting the fix here. Will
>>  happily do the PR if required.
>>
>>  Thanks.
>>
>>