Changes have been made in Git for this ticket:

Bug #9692: Fix setting current mailbox (if a virtual folder) in 
drop-down folder list

  1 files changed, 3 insertions(+), 2 deletions(-)
http://git.horde.org/horde-git/-/commit/19038252b938396298b60fd5169629dc826ab926

Sorry, sounds like we misunderstood each other. I can load the folders 
just fine too. But the drop down list doesn't "stick" at the selected 
virtual folder.

That is expected.  Should not be the issue.
I just tried on Chrome 10 and could load Virtual Folders just fine.

Yes.
Didn't help.

I noticed that the mailbox id seems to be double encoded in the URL, 
maybe this is related?
http://xxx/horde/imp/mailbox.php?mailbox=impsearch%2500vinbox

This is with Chrome.

Which drop down menu?  The one in IMP's menubar?  Works fine for me.

Did you rebuild the folder tree manually or do a logout/login?

Works great now, thanks! The only (new) issue is that the virtual 
folder is not selected in the drop down list when opening it.

I think this should fix things.  The problem wasn't the upgrading - it 
was the rebuilding of the virtual folder list inside of IMP_Search.   
After an upgrade, the virtual folders were not stored by their ID in 
the internal array, so they were not recognized as virtual folders.

Changes have been made in Git for this ticket:

Bug #9692: Fix upgrading virtual folders from IMP 4

  3 files changed, 35 insertions(+), 47 deletions(-)
http://git.horde.org/horde-git/-/commit/7c4e25ec5cdc74a4c2619e4f836e2fe7f0e0ec80

The changes I made have nothing to do with virtual folder display - 
they were solely related to issue #1 in this ticket (initial page 
preference).

The changes don't make much difference for me. Now, I have two folders 
under Virtual Folders, but:
- They still don't have the correct label
- They are not detected as virtual folders (no edit/delete links, no 
results when opening them)
- Virtual Folders (at least those converted ones) don't show up in the 
drop list any more at all.

It's wrong that this is also used as the mailbox *label* after the conversion.

Unfortunately, there is not really an easy way to convert an old 
vfolder name to a new ID.  So check for an IMP 4 virtual folder ID 
and, if found, delete the preference value.
Sure - IMP 5 doesn't recognize IMP 4 virtual folders as search 
mailboxes, so it will attempt to do all sorts of things on the IMAP 
server thinking the mailbox is a "real" mailbox.  This would cause all 
the errors.

Changes have been made in Git for this ticket:

Bug #9692: Correct strpos() usage

  1 files changed, 1 insertions(+), 1 deletions(-)
http://git.horde.org/horde-git/-/commit/bf958b5e031e0c8e04ea4878a94dfc15e81aab3e

Changes have been made in Git for this ticket:

Bug #9692: Handle virtual folders in IMP 4 initial_page pref

  1 files changed, 8 insertions(+), 3 deletions(-)
http://git.horde.org/horde-git/-/commit/4d790b8bbc700fc1b0721106502bfdca6615e3d7

Those are correct vfolder names.  What do you think is wrong with 
those?  (The null character is expected and necessary)

I see two issues with upgrading of vfolder preferences:

1) The initial_page pref needs to updated, if it contains **search_......
Sidenote: is there any reason why the notification message about 
mailbox not found is displayed 3 times in the interface and 19 times 
in the log?

2) The vfolder pref is not correctly converted.
To test this, I created a fresh vfolder preference in IMP 4 and 
migrated that to IMP 5. The original preference value was:

a:1:{s:22:"45lr2nhothesccksok8kco";a:5:{s:5:"query";s:378:"O:21:"IMP_IMAP_Search_Query":8:{s:4:"_and";a:1:{i:0;a:1:{i:0;O:21:"IMP_IMAP_Search_Query":8:{s:4:"_and";a:0:{}s:15:"_extendedSearch";a:0:{}s:6:"_flags";a:0:{}s:4:"_not";N;s:3:"_or";a:0:{}s:6:"_query";s:12:"BODY 
"horde"";s:5:"_size";N;s:7:"_sizeop";N;}}}s:15:"_extendedSearch";a:0:{}s:6:"_flags";a:0:{}s:4:"_not";b:0;s:3:"_or";a:0:{}s:6:"_query";N;s:5:"_size";N;s:7:"_sizeop";N;}";s:7:"folders";a:5:{i:0;s:27:"INBOX.Mailinglisten.Bugtraq";i:1;s:25:"INBOX.Mailinglisten.Cyrus";i:2;s:25:"INBOX.Mailinglisten.Kolab";i:3;s:28:"INBOX.Mailinglisten.pear-dev";i:4;s:27:"INBOX.Mailinglisten.php-dev";}s:6:"uiinfo";a:10:{s:5:"field";a:4:{i:0;s:4:"from";i:1;s:2:"to";i:2;s:7:"subject";i:3;s:4:"body";}s:9:"field_end";i:4;s:5:"match";s:3:"and";s:4:"text";a:4:{i:0;s:0:"";i:1;s:0:"";i:2;s:0:"";i:3;s:5:"horde";}s:8:"text_not";N;s:4:"date";N;s:7:"folders";a:5:{i:0;s:27:"INBOX.Mailinglisten.Bugtraq";i:1;s:25:"INBOX.Mailinglisten.Cyrus";i:2;s:25:"INBOX.Mailinglisten.Kolab";i:3;s:28:"INBOX.Mailinglisten.pear-dev";i:4;s:27:"INBOX.Mailinglisten.php-dev";}s:12:"save_vfolder";s:2:"on";s:13:"vfolder_label";s:5:"Horde";s:4:"mbox";N;}s:5:"label";s:5:"Horde";s:7:"vfolder";b:1;}}

The converted is:

a:2:{i:0;C:25:"IMP_Search_Vfolder_Vinbox":30:{a:2:{s:1:"e";i:1;s:1:"v";i:1;}}i:1;C:18:"IMP_Search_Vfolder":378:{a:6:{s:1:"c";a:1:{i:0;C:23:"IMP_Search_Element_Text":29:{[1,{"b":1,"n":0,"t":"horde"}]}}s:1:"e";i:1;s:1:"i";s:23:"xEDdYxPcj3hNh86y1_NxbqA";s:1:"l";s:5:"Horde";s:1:"m";a:5:{i:0;s:27:"INBOX.Mailinglisten.Bugtraq";i:1;s:25:"INBOX.Mailinglisten.Cyrus";i:2;s:25:"INBOX.Mailinglisten.Kolab";i:3;s:28:"INBOX.Mailinglisten.pear-dev";i:4;s:27:"INBOX.Mailinglisten.php-dev";}s:1:"v";i:1;}}}

The problem with the latter is that it result in those vfolder labels and ids:

impsearch\0vinbox
impsearch\0xEDdYxPcj3hNh86y1_NxbqA

\0 is the nul character.