Create the following structure:
```
A\app.js
B\app.js
C\
```
Now select both app.js files, cut, and paste them into C.
One will be moved, the other will pop an error dialog but will be deleted.
```
A\app.js
B\app.js
C\
```
Now select both app.js files, cut, and paste them into C.
One will be moved, the other will pop an error dialog but will be deleted.