AssertJ not clicking boxes - Java 11

#### Summary
I’m not able to use basic click functionalities with AssertJ (basically everything related to activating buttons)

Opened a [thread](https://stackoverflow.com/questions/53379005/assertj-not-clicking-boxes) about it in STO as well -

I’m not sure if it’s a regression or if I’m just missing out something obvious… the example here - [Example](https://github.com/joel-costigliola/assertj-examples/blob/master/assertj-swing-junit-examples/src/test/java/org/assertj/swing/junit/examples/getting_started/SimpleCopyApplicationTest.java) is not working on my env as well (Java 11)

#### Example

The GUI is a JPanel and I use Containers.showInFrame to display it.

The panel has some text fields, JCheckboxes and JComboboxes.

I'm able to set text in the text fields, but I am not able to check/select the boxes. Been breaking my head but couldn't figure out what is missing...

Working:
```java
frame.textBox("example").setText(result).requireText(result);
```
Not working:
```java
frame.checkBox("exampleCheckBox").uncheck().requireNotSelected();
frame.checkBox("example2CheckBox").check().requireSelected();
panel.comboBox("exampleComboBox").selectItem(2);
```
The component description that I get for a checkbox is:

`[javax.swing.JCheckBox[name='exampleCheckBox', text='Mandatory', selected=true, enabled=true, visible=true, showing=true] - property:'selected']`

Using Java 11, Gradle build, latest assertj-swing-junit and assertj-core.

Would highly appreciate any leads!
Thank you

Beginnen Sie mit assertj-examples/assertj-swing-junit-examples/src/test/java/org/assertj/swing/junit/examples/getting_started/SimpleCopyApplicationTest.java und reproduzieren Sie die Aktionen für das Kontrollkästchen und das Kombinationsfeld unter Java 11. Vergleichen Sie die funktionierende Interaktion mit dem Textfeld mit den fehlschlagenden Steuerelementen und untersuchen Sie die gemeldete Komponentenbeschreibung. Als erledigt gilt die Identifizierung der Ursache und die Bereitstellung eines verifizierten Fixes oder einer klaren Lösung für diese Interaktionen.

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