Completion of type tags in FXML editor for file in Java 9 project fails

[hallvard]

When using the FXML editor on an fxml file in a Java 9 project, it doesn't propose types, e.g. when entering <Text nothing is proposed. Properties of the parent tag are proposed, so it seems to be about type info, not completion in general. My e(fx)clipse version is 3.1.0, Eclipse is 4.7.2, Java is 9.0.1 on Mac

BTW, completion of types works in the Java editor.

I get exceptions like this in the error log, but not when asking for completion. Don't know if it's helpful

Java Model Exception: Java Model Status [Text.class [in javafx.scene.text [in module:javafx.graphics]] does not exist]
at org.eclipse.jdt.internal.core.JavaElement.newNotPresentException(JavaElement.java:560)
at org.eclipse.jdt.internal.codeassist.SelectionEngine.selectType(SelectionEngine.java:1540)
at org.eclipse.jdt.internal.core.NamedMember.resolveType(NamedMember.java:317)