Dreamweaver freezes when switching to another window

Hi, I'm encoutering something really troublesome. While I was selecting the font family which was not yet available for CSS in Dreamweaver, I switched to Chrome to see the collection of fonts that I needed to choose then when I came back to Dreamweaver to type them down, and it freezed. I try several times, just switching to another program's windown but the result is still the same, which is very irritating. 

Do anyone knows how to fix this situation ? Thank you.