GCPad Config Issues

[LilBTheBasedGod]

Today I received my "GC Controller Adapter for PC"... Here's a pic:

Spoiler: (Show Spoiler)

It works great and I know it's working as an input and I've installed the drivers for it correctly. I've gotten all the buttons and vibration to work through the windows game controller setup.

However, when I try to set this up with Dolphin, the following happens.. I select GCPad at the top of Dolphin, select the drop down box to click my usb game controller (my gamecube controller) and after clicking the device i want to use the box just goes blank (refer to this image):

Spoiler: (Show Spoiler)

As you can see it won't let me select a device and the only way I can get it to work is by going back to the default of my keyboard/mouse and it only lets me configure that.
If anyone has any ideas please throw them at me because this is quite frustrating. Thanks for any input.

Edit: I'm going to tell a few things I've already tried..
I've tried restarting my computer thinking it was a driver issue.
I've tried uninstalling and re-installing the drivers for my adapter.
I've tried uninstalling and re-installing multiple versions of dolphin and deleted the config files in my documents folder.
Also, I'm running this on Windows 7.

[MayImilae]

That's a windows bug. It still works even though it's blank. Just fill it out, hit ok, and then come back and it will have the right device in the dropdown and all your bindings will still be there. If you want the reassurance of it not being blank while you fill out the bindings, just press the refresh button after you select a device in the dropdown, and it will show up.

It was fixed by 4.0-40, so use development builds if it bothers you.

https://code.google.com/p/dolphin-emu/issues/detail?id=6224