Double Click Broken on XP

I've just done a whole series of bug fixes and upgrades, including updating to the latest JUCE for a plugin.  However in Windows XP, with my plugin loaded and open double click has stopped working.  

It's only affecting XP as far as I can tell. 

Any suggestions as to where to look before I build an XP dev box with a copy of Visual Studio etc. etc.

thanks!! J.

Hmm. I'm very sceptical about that.

All the code involved in double-click detection is platform-agnostic, so if you're getting different behaviours on different OSes, I think you may be mis-diagnosing something else..

I skeptical too.  But my beta tester has the problem and I have it replicated here on a VM... 

Let me have a think about how to rule out anything else. 

Here's the test I'm doing.  With the plugin Window open I go back to the host.  I open the 'Save...' file chooser from Reaper. 

I try to open a folder by double clicking..  Nothing happens. 

I can open the folder by right clicking and choosing Select from the hosts pop-up menu. 

I close the plugin, I can now open the folder normally by double clicking!

I get the same effect in VSTHost as well on my XP VM.

And just in case I was going mad, I've repeated the same test again on Windows 7 in VSTHost as well as Reaper and it's fine.  Very strange. 

The problem occurs in VSTHost without opening the editor.  In Reaper the problem goes away when I close the editor window. 

.. Downloading an MSDN copy of XP and Visual Studio 2010 .. I feel a debugger coming on ... 

So you mean double-clicking is working in the juce window, but not in the host!?

I'll double check tomorrow morning. But it's definitely failing in the host.  I think it's working in the plugin in the preset manager..will check. 

Yes - confirmed - works in plugin, fails in host.

That's completely bizarre! I can't think of any way the plugin's window could possibly affect the host like that..

It can't be a mouse-hook, because the only hooks that are used are for mouse-wheel and keyboard events, not for mouse-clicks.

Does this happen with the juce demo, or just your own plugin? All I can think is that perhaps your window is repeatedly grabbing the focus or doing something that's interrupting the events from being dispatched correctly...

I'll try the JUCE demo plugin and see how that goes...I'd not tried that.  

I haven't yet copied the code across onto my nice new XP VM :)

Instead I've been sucked into this logging singleton bug you just kindly replied to...