Hi David,
You have to substantiate the xmlfragment in your controller. Try this code in your onInit -
this._getFragment = sap.ui.xmlfragment("+ Provide the fragment path namespace +", this); this.getView().addDependent(this._getFragment);
For more reference, you can check my sample where I used a dialog fragment. Inside the dialog I have two inputs placed. When you put a breakpoint on HomePage.controller.js Line #11 and Line#17. You can see attachValidationError and attachValidationSucess getting fired.
Sample - Plunker - InputHighlightError
Regards,
Sai Vellanki.