[Plugin: tagaroo] Image upload broken with Tagaroo

Same problem as here:
https://www.ads-software.com/support/topic/image-upload-problem-and-tagaroo-plugin

Clicking to upload/insert an image opens the window full screen in a new tab instead of the Javascript popup. Then the image can’t be inserted into the post (white screen of the death). With my installation Tagaroo did not cause problems with posts but with pages. I tried reuploading the include directory of WP with no success.
Disabling Tagaroo fixes the problem, so there is probably a Javascript conflict.