<Swing Dev> Weird focus problem with JTextField

[Clemens Eisserer]

Hi Pavel,

I was able to distill the problem to small, self-contained testcase,
which is available at: http://93.83.133.214/textfielddemo.zip
I've also created a short video, demonstrating the issue:
http://youtu.be/r1JDj5BuBOM

The JTextField opens up a JPopupMenu on <ENTER>, which can be closed
by clicking the JButton it contains.
However, after the popup is hidden, no editing is possible unless
focus is toggled once between the browser and another window.

Unfourtunatly the testcase only triggers the problem on Linux (tested
with jdk8+oracle plugin as well as openjdk7+icedtea-web both with
recent versions Firefox and Chrome), However, I've seen this issue
happen on Windows too when running the application I talked in the
first email.

It would be great if you could have a look.

Thank you in advance, Clemens


2011/7/30 Pavel Porvatov <pavel.porvatov at oracle.com>:
> Hi Clemens,
>
>> Hi,
>>
>> I've developed a database applet where Swing widgets are connected to
>> RowSets using the SwingSet library (an old sourceforge project).
>> All queries are executed on the EDT, except for some background tasks
>> which sync with the UI using SwingUtilities.invokeLater().
>>
>> When running the application over high-latency connections (EDT is busy
>> for a few seconds), sometimes after a pending operation is finished I can't
>> edit any JTextFields. The mouse-cursor changes when I move it over the
>> JTextField, but when I click into the JTextField the carret simply does not
>> appear - everything else (JMenu, JButtons, ...) works as expected - so I
>> guess event delevery is still working as expected.
>> To make JTextField-editing work again, I have to transfer focus to another
>> native window and back to the browser-window. A heavyweight JMenu makes it
>> work again too, whereas a lightweight one doesn't help.
>>
>> Even worse, the problem does not manifest itself with low-latency
>> connections or when running as application.
>>
>> I am completly puzzled :/
>> Any idea what could be the problem, or where / what for I should start
>> looking?
>
> First of all it's not a good idea to keep the EDT thread busy for a long
> time and I think the best way is to rewrite application.  Could you please
> make a small separated application that emulates EDT blocking and shows the
> problem?
>
> Regards, Pavel