Drag and drop file out of Mp3tag into ...

Dragging the music file from Mp3tag to force Spek, this file is removed of the list! But the Tag&Rename is not removed.
See (or download) video - link:
Why is that?
Threw players WinAmp or BSpleier file is not thrown out of the list.

Spek : http://spek-project.org/

Drag&Drop is an interaction between 2 programs.
After a D&D action the receiving program gives a feedback of what the action should be interpreted.
The possible feedback ist the following:
0 DROPEFFECT_NONE Drop target cannot accept data.
1 DROPEFFECT_COPY dropping invokes copying.
2 DROPEFFECT_MOVE dropping invokes a move
4 DROPEFFECT_LINK dropping creates a link

The source application then acts accordingly. So apparently some of your applications report "move" and others "copy". Mp3tag does not influence these applications.

So the problem has a Spek application?

I do not know if it is a problem for the application. I assume that this application gives MP3tag the feedback that the d&d-action invoked a "move" so that the files should no longer be seen in the MP3tag files list.