[FLEX-27218] Mouse selection using Ctrl+click then Shift+click works wrong in TileList when offscreenExtraRowsOrColumns > 0

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: Adobe Flex SDK 3.2 (Release)
• Component/s: mx: TileList
• Environment: Affected OS(s): All OS Platforms; Affected OS(s): All OS Platforms; Language Found: English
• Assignee: Unassigned
• Reporter: Adobe JIRA
• Created: 04/Apr/11 01:24
• Updated: 04/Apr/11 01:24

Description

The bug is actual for latest (4.1) Flex SDK as well.

Steps to reproduce:
1. Run attached TileListTest.swf
2. Scroll down for some lines
3. Select an item using Ctrl+click
4. Select another item using Shift+click

Actual Results:

Selection related to anchor item placed above the expected anchor item. Furthermore, when you select items between expected and actual anchor, all items up to top are selected.

Expected Results:

Selection related to anchor item chosen by Ctrl+click.

Workaround (if any):

Problem in ListBase.selectItem() - it has 3 execution flows:
a) without Shift/Ctrl
b) with Shift
c) with Ctrl

Cases a) and c) change anchor item, but do this in different ways:
a)
iterator.seek(CursorBookmark.CURRENT, _selectedIndex - indicesToIndex(verticalScrollPosition - offscreenExtraRowsTop, horizontalScrollPosition - offscreenExtraColumnsLeft));

c)
iterator.seek(CursorBookmark.CURRENT, index - indicesToIndex(verticalScrollPosition, horizontalScrollPosition));

I.e. Ctrl+click selection ignores offscreenExtraRowsTop/offscreenExtraColumnsLeft.

Changing c) case according to a) fixes the problem. Monkey patch can be used as workaround.