Add the Open from Damned Lies(DL) button

A user can view two buttons in the main window when no file is opened.

These buttons are namely: Open & Open from DL.

However, if a file is opened, the user can view only the Open button

Thus, a user cannot load files from Damned Lies.

To fix this make the Open from DL button visible when a file is opened.

Closes #65 (closed)