New subject: [Bug 13374] ComboBoxEx list get selected on mouse button down and release

23 May 2008


      http://bugs.winehq.org/show_bug.cgi?id=13374
Summary: ComboBoxEx list get selected on mouse button down and
                    release
           Product: Wine
           Version: CVS/GIT
          Platform: PC
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: comctl32
        AssignedTo: wine-bugs@winehq.org
        ReportedBy: dylan.ah.smith@gmail.com
Created an attachment (id=13272)
 --> (http://bugs.winehq.org/attachment.cgi?id=13272)
comctl32: Added tests to show a ComboBoxEx bug caused by incorrect focus change
The quickest way to see the error is to use Wine's clone of wordpad.  There are
two dropdown lists (ComboBoxEx controls) that are on the toolbar.  Click the
button to drop down the list, then left click on an item in the list.  You will
probably notice that the wrong item is selected, and if you do it slowly (i.e.
hold down the mouse button for a second then release it), then you will notice
that the selection is made and the list disappears when the mouse button is
pressed, and when it is released another selection is made even though the list
has disappeared.
I ran wordpad on Windows XP SP2, and noticed that the correct behavior is the
item is only selected when the mouse button is released.
Note that there are two other separate bugs that you might notice:
- The font size is 0 to start with (richedit bug)
- Selecting a new font size will give you an "Invalid number format" error when
the control loses control (wordpad bug)
- The selected items from the list are not applied until the combobox loses
focus (wordpad bug)
I have submitted patches that fix these other bugs to the wine-patches mailing
list.
I have done some created tests that show the bug is in ComboBoxEx from the
comctl32 and not in ComboBox from the user32 dll.  I have attached the patch
that adds these, and will submit it to the wine-patches mailing list after I
get the bug number to mention in the commit message.
I did some debugging, and to my suprise it was a call to SetFocus was rolling
up the ComboBoxEx's list.  Digging deeper I found it was actually the
WM_KILLFOCUS call to the window that previously had focus, which was the
ComboBox (a child of ComboBoxEx).  The ComboBox saw that it was losing focus,
and what was losing focus it didn't recognize as itself, it's edit control, or
its list control, so it incorrectly decided to roll the dropdown up.  It turns
out that what was losing focus was an edit control that ComboBoxEx and child
ComboBox control didn't know about created since, oddly enough, native Windows
does not use the child ComboBox's edit control.
My tests for ComboBox and ComboBoxEx show what had focus before and after
pressing the dropdown button, and selecting an item in the dropdown list.  In
both causes the top level (main) window had intial focus.  With ComboBox the
focus was correctly on the edit control after each of the mouse button up/down
messages are sent.  For ComboBoxEx the focus was supposed to be on ComboBox
when the list is dropped down then on the edit control after it's rolled up,
according to my crosstests, but instead it was on the edit control after the
list is dropped down.  Some debugging found that the focus was being changed to
the ComboBox, but each time it did that, the ComboBoxEx was notified with a
CBN_SETFOCUS command message, which had no case for it in the COMBOEX_Command
function, so the default case was used.  The default case contains two lines
that sets the focus back to the edit control, thus causing the bug, however
taking out those lines caused missing notifications of the change.
Hopefully this is enough information for someone else more familiar with the
code to properly fix the problem.
-- 
Configure bugmail: http://bugs.winehq.org/userprefs.cgi?tab=email
Do not reply to this email, post in Bugzilla using the
above URL to reply.
------- You are receiving this mail because: -------
You are watching all bug changes.

[Bug 13374] New: ComboBoxEx list get selected on mouse button down and release