Image Select Window Bug

Hi,
I have a really frustrating bug.
The Image Select Window that pops up when you want to give a product a image does not pop up anymore.
It does not matter where i try it. I can try it to set the image of the store or add a imange in html content.
The window does not appear anymore. My screen gets grey but the window is not there.

Regards

Kurtisane

Check the chrome console and see if there are any errors in it.