Hi lopen -
One thing I've noticed is that if you move the mouse with the 1PW Mini menu open then it loses focus. This happens regardless of whether Dropzone is open or not. This is an issue in 1PW mini and not with Dropzone.
Could this be the issue you're seeing here? I'm running the latest version of 1PW 4 (Version 4.0.9) and I'm pretty sure the original issue (mini losing focus after a second with Dropzone open) is fixed. You may want to close Dropzone and verify that it's not really an issue with 1PW.
If you still think it's a Dropzone issue, please record a short screencast showing the issue and link here. I've been proved wrong before!