Proper way to open media in Source view window?

I got very confused about opening media in source view window (in media page mostly).

Sometime double click on file works, and sometime it doesn't, sometime dragging clip to view window works and sometime it doesn't. It makes no sense and what strange, you can't be sure opened it or not, especially for similar shots, you need to compare names of the file with source view title (what takes time if you have hundreds of files)

Is the a proper 100% way to open selected file in source window?

In the Edit page I just double click on the thumbnail, but you can also click on it and drag it to the Source window.
On the Media page a single click on a thumbnail will place it in the window. If it is not consistent maybe your mouse is starting to fail.