Cannot add tag to media document using d&d

Hello everyone.
When working whith the media browser, I expect do be able to add tags to a document, by dragging the document to the tag.
While trying this, the tag is highlighted and it shows some dots as a “processing” indicator, when I drop the document.
However, after that, the document is opened, in the window, where I can edit meta data like title, tags, collections etc. The tag, I choose, is not selected.
I have to select it there and save the document.
Administrating large media collections is time consuming this way.
What is wrong here?
Can anybody please help me?

Version: Neos 4.1.7

Best regards