You can see it on the image:
http://aurora-ds.ru.oracle.com:9500/runs/81833.ManualSubmit-1/workDir/javafx/scene/control/test/chart/NumberAxisTest_cssTickLabelFont/NumberAxisTest-CSSTickLabelFont.png

Label, related to the top of vertical axis is not shown, label 7,5 doesn't fit, one zero is shown as "0", the other, as "0,0".