LightboxIT.openMissingImage is flickering

Index 0 out of bounds for length 0

java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0
	at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:64)
	at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:70)
	at java.base/jdk.internal.util.Preconditions.checkIndex(Preconditions.java:248)
	at java.base/java.util.Objects.checkIndex(Objects.java:372)
	at java.base/java.util.ArrayList.get(ArrayList.java:458)
	at org.xwiki.image.lightbox.test.po.LightboxPage.getImageElement(LightboxPage.java:67)
	at org.xwiki.image.lightbox.test.po.LightboxPage.hoverImage(LightboxPage.java:54)
	at org.xwiki.image.lightbox.test.po.LightboxPage.openLightboxAtImage(LightboxPage.java:79)
	at org.xwiki.image.lightbox.test.ui.LightboxIT.openMissingImage(LightboxIT.java:305)