you can see your BrowseButton in action here: http://filetree.extjs.eu
I found some issues, don't know yet if it's because of my misconfiguration or bugs:
- BrowseButton doesn't open file dialog in Opera neither Winblow$ nor Linux version
- When it is in bbar (menu button at the top-left corner) it doesn't seem to work reliably in IE7 after adding several files - even after I've removed doctype
- Works perfect in Firefox
Issues 1 and 2 are of no importance for me as I force my users to use Firefox but they can matter for others.
You can download zip here.