<Page xmlns="http://www.nativescript.org/tns.xsd" loaded="onLoaded">
  <Page.actionBar>
    <ActionBar title="{{ customTitle }}" />
  </Page.actionBar>
  <StackLayout>
    <Label text="blah1" />
    <Label text="blah2" />
    <Label text="blah3" />
  </StackLayout>
</Page>

var Observable = require('data/observable').Observable;
var viewModel = new Observable({ customTitle: 'hello??' });

exports.onLoaded = function(args) {
  args.object.bindingContext = viewModel;
};

This doesn't work. This causes a freezing crash with a blank error.

However, if I change the action bar title to this:

<ActionBar title="{{ customTitle + 'awefawefawef' }}" />

This works. It will show hello??awefawefawef. So pretty much I have to workaround this freezing crash by doing <ActionBar title="{{ customTitle + '' }}" /> to make it work.

In addition, when it DOES work, my stack layout (shown above) ends up getting overlapped by the action bar instead of going below the action bar.

This is {N} 1.4.3 in the browser-based Telerik Platform.