[FLEX-26242] DataGroup with virtual layout is inefficient when renderers are reused

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Cannot Reproduce
• Affects Version/s: Adobe Flex SDK 4.1 (Release)
• Component/s: Spark: DataGroup
• Environment: Affected OS(s): All OS Platforms; Language Found: English
• Assignee: Adobe JIRA
• Reporter: Adobe JIRA
• Created: 14/Dec/10 03:51
• Updated: 27/Dec/10 14:00
• Resolved: 21/Dec/10 16:14

Description

Steps to reproduce:
1. Create a DataGroup with any layout having useVirtualLayout=true
2. Do something that will change the number of renderers, for example reduce then expand again the width of the dataGroup

Actual Results:
layout.updateDisplayList is invoked twice per atomic operation

Expected Results:
layout.updateDisplayList is invoked once

Workaround :
None

Reason:
Everytime a renderer is reused, its includeInLayout property is reset to true, invalidating the parent. Because GroupBase override invalidateDisplayList, the safeguard in UIComponent normally preventing invalidation occuring from updateDisplayList is not used.