wxTreeCtrl + wxTR_MULTIPLE flag: SEL_CHANGED only fires on item focus change

[jmikulasek]

When you have a wx.TreeCtrl instance with
a wx.TR_MULTIPLE style the wx.EVT_TREE_SEL_CHANGED
event is not always triggered when deselecting a node
while pressing Ctrl.

It can be demonstrated in the wxPython demo. When I
uncomment the wx.TR_MULTIPLE style flag and select
several items while pressing Ctrl (so all stay selected)
and then deselect the LAST selected item (still pressing
Ctrl), nothing gets printed in the log window.
It is interesting that when you try it on leaf nodes,
the icon changes, but the event is not triggered.

I am running Windows XP, Python 2.4, wxPython 2.5.3.1
(unicode).

[neis]

Confirmed to still be a problem with wxMSW-2.8.7 (probably C++ mode, this time), see mailing list archive of May 2008, Subject: "wxTreeCtrl with the style wxTR_MULTIPLE, missing events".

[mspacek]

I can also confirm this in wxMSW-2.8.8.0 (WinXP SP3) from wxPython. It seems that wx.EVT_TREE_ON_SEL_CHANGED/CHANGING are only fired when the currently focused tree item (with the dotted rectangle around it) changes, and not when the actual selection changes. When wx.TR_MULTIPLE flag is not set, this doesn't matter, since the currently focused item and the currently selected item are always identical. But that's not necessarily the case when wx.TR_MULTIPLE is set. I think the original report is a symptom of this: if you try deselecting the last selected item (CTRL+left click) in the tree, you change its selection, but not its focus, and hence the event doesn't fire.

To demonstrate, uncomment wx.TR_MULTIPLE in the TreeCtrl.py demo in wxPython, run it, select an item in the tree, hold down CTRL, then move up and down with the cursor keys. SEL_CHANGED events will fire on every item focus change, even though the selection hasn't changed. Now focus some event, then try (de)selecting it with CTRL+left click or CTRL+space. In this case, SEL_CHANGED won't fire.

[mspacek]

Looks like a duplicate of #626

[mspacek]

Whoops. EVT_TREE_ON_SEL_CHANGED above should be EVT_TREE_SEL_CHANGED

[mspacek]

#4448 regarding EVT_LEFT_DOWN is probably related

[Scary]

I have added a patch to #9570 which attempts to fix these issues. Please give it a try and let me know what you think. I hope it is helpful. Thanks!
-Chris Edwards

[vadz]

I think this one doesn't add anything compared to #9570 and #626 so closing it as duplicate, please reopen if I missed something specific to this bug.

Thanks!