LO v4.2 won't let me enter file name writer document. Keyboard lockout. Linux OS.

I have two problems. LibreOffice v4.2 on Linux Mint 17 will not let me edit the document after I’ve changed the font.

Second problem: If I try to save the document (to be re-opened later) the save box will not let me type a document filename. The keyboard seems locked out.

Why are either of these problems occuring?

I would reset my user profile. For details please refer to: https://wiki.documentfoundation.org/UserProfile