A bug in Flex SDK 3.4?? FocusManager.focusInHandler() -

I have recently upgraded from Flex SDK 3.3 to SDK 3.4. Now I can completely get this error message in full application:

  TypeError: Error # 1009: Can not use the property or method of a blank object reference. MX. Manager :: Focus Manager / Focus Inhandler () [C: \ Autoblog \ Gallaga \ Frameworks \ Projects \ Framework \ src \ mx \ managers \ FocusManager.as: 601]  

This happens Very random, but most often when I click on the tab in Tab Navigator, the problem is fixed when I will add a 'FEBUL = "false" attribute to Tububivator, but I would like to focus on Tab Navigator, and I'm sure As my app Can not fail all the elements.
Someone told me that this is a bug in SDK Is this true? If so, is there any other way than 'Focus Lol =' False '?

Definitely There are problems with updating SDK to 3.4 in this type of I have seen it on many other types of classes. I found that to rebuild the project in reform or to rebuild my work area - in my experience it is corruption in the field and in SDK There is no problem.

I have also seen a problem where you can refer to the library that was compiled using the previous library - in particular I have seen such issues while shaking 3.2 and 3.3.

I'm not 100% confident that this is your exact problem and I am sorry to offer anecdotes instead of just addressing the root causes, but in my experience, this kind of thing is about many environmental-specific issues It is difficult to find out, therefore, it is difficult to find out.

In my case this problem was "flash" package, but it looks like this. I have but your mileage is different, Hopefully it can be different, it helps - if it is not, then comment.