Problem with null pointer in updateTab function

[senordhuff]

Hi,

I am seeing a problem that seems to happen intermittently with this line of code in the updateTab() function. We are trying to call updateTab and passing a null property to remove the tab but maintain the pane as suggested in other posts in the forums.

var _6=this.getTab(_1);
//other code
return _4.pane=_6.pane=null;

I've debugged this enough to see that sometimes _6 is undefined and so we get the following error:

14:42:45.134:TMR1:WARN:Log:TypeError: Cannot read property 'pane' of undefined
    unnamed() @ 
    TabSet.updateTab()
    unnamed()
    [c]Class.fireCallback()
    Timer._fireTimeout()
    unnamed() @

This is with an 8.0 nightly and seems to only happen on Google Chrome for some reason. But, again, only about 50% of the time. What could cause _6 to sometimes be undefined during identical test sequences?

[Isomorphic]

This suggests that a tab was added, then before the tab was drawn, updateTab was called to set it's pane to null. There's no obvious reason this would be Chrome-specific. We've put in a fix that will definitely avoid the _6 is undefined issue, but the pattern of calls required to get to this state is somewhat odd and may indicate an application-level bug.