VBA - Application Filedialog Hidden Behind Outlook

Outlook version
Outlook 2010 32 bit
Email Account
Exchange Server
Hi all,
I have written a small macro in Outlook 2010.
I have a button on a form which opens a filedialog (I use Word filedialog) in order to select a filesystem folder.
At first it was working great.
After a few weeks the filedialog started opening behind the Outlook window and it seems like Outllok "froze". I have to minimze it by pressing outlook on the tray and then I cna see the dialog.

I don't know what changed during that time, maybe I installed an automatic Windows7 update???

I tried disabling Add ins, launch Outlook with the /safe switch but it didn't help.
If I use, on the same machine, a shell32 BrowseForFolder Dialog it's working great but the shell32 dialog is not good for my needs.

Any help would be greatly appreciated