Using Build ID: 2002020103 Steps to reproduce problem: 1. Open messenger 2. Collapse the folder pane (sidebar). 3. Close messenger 4. Open messenger Actual results: [JS Console] Error: selection has no properties Source File: chrome://messenger/content/mail3PaneWindowCommands.js Line 891 Error: folderOutliner.outlinerBoxObject.selection has no properties Source File: chrome://messenger/content/msgMail3PaneWindow.js Line 980 [Console] TypeError: outliner.outlinerBoxObject.selection has no properties CC'ing bryner because Jan thought he might know why the outliner isn't working in a collapsed box any more.

Oh, and this definitely worked 10 days ago...

I get those errors, but I don't seem to lose functionality; I can open the folder pane, select a folder and the folder contents are shown in the threadpane (sorry, if this was obvious; just distinguishing between the 'error needs fixing' and 'this is totally broken' cases).

Believe it or not, but I'm used to messenger automatically downloading mail on startup and allowing me read all my mail and groups using the Next button without actually once looking at let alone clicking the folder pane.

*** Bug 123719 has been marked as a duplicate of this bug. ***

I would like this problem fixed very soon if this is indeed tha cause of the problem described in Bug 123719.

nsbeta1- per Nav triage team, ->1.2. Product is designed for primary use with an open folder pane, with no other way to switch folders or servers makes this a low-percentage scenario - affects few people. Mail is still functional after opening folder pane; bug reorders servers and folders, but only while that window is open. Low impact. Workaround: leave folder pane open.

20 weeks later, regression is finally fixed by patch in bug 123729.