Closed due to a lack of feedback. Please leave a reply if there's new information.

Works for me, tested on the run dialog (Win+R).
Perhaps you've encountered it with a window which uses custom thumbnails as tabs (e.g. like IE does), and then the minimizing mechanism is different, and there's no way to force it to minimize.

I can't reproduce it. The group stays expanded until you move the mouse out of the group on my PC.
Please provide more details, such as OS version, taskbar properties, and tweaker options.

I couldn't reproduce the issue.
In general, "Open with" is a feature of Windows, but you have to hold Shift while dropping to make it work. The tweaker only makes Windows think that Shift is being held.
Try to turn off the tweaker, and use Shift. Do you still encounter the issue? If yes, then it's probably not the tweaker's fault.

Hi Guido, 

Unfortunately I don't speak German, but I've translated the text using Google Translate, and I understand that you like 7+ Taskbar Tweaker and find it useful. Thank you for the positive feedback!

I believe that it's possible to achieve this with taskbar properties if you're using Windows 8 or above.

Closing as a duplicate:
http://tweaker.userecho.com/topic/382920-after-wak...

Unfortunately, I cannot reproduce this bug. All I know is that it's caused by the autoupdate checker, and by looking at the reports you can conclude that the bug occurs only on Windows 7. Perhaps it's a bug of Windows, I don't know.

This is not the same issue as the one the pre-Windows 8.1 Update 1 version.
Please see my reply here:
http://rammichael.com/7-taskbar-tweaker/comment-page-17#comment-3660

v4.5.1