I have an MVVM application. In one of the ViewModels is the 'FindFilesCommand' which populates an ObservableCollection. I then implement a 'RemoveFilesCommand' in the same ViewModel. This command then brings up a window to get some more user input. 

Where/what is the best way to do this whilst keeping with the MVVM paradigm? Somehow 
doing: 

```
new WhateverWindow( ).Show( ) 
```

in the ViewModel seems wrong.

Cheers,

Steve