After upgrade to 2.7,error stack trace gone,How to get it back?

Hello
      As you know,pre v2.7,if an error occurred,java error stack trace will tell us where(exact line) and why it happened,but right now,I only got something like this:

Uncaught com.google.web.bindery.event.

shared.UmbrellaException: Exception caught: Exception caught: Exception caught: Exception caught: Exception caught: (TypeError) : Cannot read property 'ordinal_3_g$' of undefined
castFireEvent_0_g$  @   athena-0.js:149686
fireEvent_7_g$  @   athena-0.js:149710
fireEvent_2_g$  @   athena-0.js:13276
onCreateButtonClicked_4_g$  @   athena-0.js:72077
onBrowserEvent_13_g$    @   athena-0.js:72203
dispatchEventImpl_0_g$  @   athena-0.js:270336
dispatchEvent_4_g$  @   athena-0.js:270325
dispatchEvent_6_g$  @   athena-0.js:272229
apply_44_g$ @   athena-0.js:224696
entry0_0_g$ @   athena-0.js:224766
(anonymous function)    @   athena-0.js:224732

 and I took 30 mins to locate where this error occurred,then fix it in 5 seconds .And realize that above error message displayed in chrome console almost uselessness,so is it to get error stack trace back?or how to got useful error message in js?

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