[FLEX-22719] API changes in ViewStack, TabNavigator and Accordion containers cause older Flex code not to compile with SDK 4.0 and Flash Builder 4 Beta2

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Not A Problem
• Affects Version/s: Adobe Flex SDK 4.5 (Release)
• Component/s: mx: Accordion, mx: Tab Navigator, mx: View Stack
• Environment: Affected OS(s): Windows; Affected OS(s): Windows XP; Language Found: English
• Assignee: Adobe JIRA
• Reporter: Adobe JIRA
• Created: 12/Jan/10 12:29
• Updated: 05/Mar/10 16:19
• Resolved: 05/Mar/10 16:19

Description

Steps to reproduce:
1. Try to compile using the SDK 4 and Flash Builder 4 Beta2 an app that uses the statement ViewStack.removeChild(ViewStack.selectedChild) or basically any code using the Accordion, TabNavigator or ViewStack "selectedChild" property, that used to be type of Container in SDK3

Actual Results:
Compilation error: Implicit coercion of a value of type mx.core:INavigatorContent to an unrelated type flash.display:DisplayObject.

Expected Results:
The file compiles with no errors. I noticed the offending 3 containers have changed the API in SDK 4.0.0 for the "selectedChild" property, which is now type of INavigatorContent, an interface that's newly introduced by SDK4 - and that's the cause of the error

Workaround (if any):
Could not find any. The "Use Flex3 compatibility mode" Flex Compiler option, available via Flash Builder 4 Beta2 does not resolve the problem
I am using Flash Builder 4 Beta2 (which ships with SDK build 4.0.0.10485) and trying to compile a project that was written with FlexBuilder3 and SDK 3.2