LCS Fantasy Lags my browser when I try to do a roster change?

Whenever I have the Fantasy page pulled up in another tab and I try to move from roster to add/drop or match ups it will completely freeze up that tab and every tab I have open will slow down tremendously. Just now I tried to open up the fantasy page and go to roster then when I checked this tab it was completely frozen. AS soon as I close the fantasy tab every works normally. This lag affects YouTube videos making them run frame by frame, any other page just completely freezes. I cant remember exactly when this started happening but I know for a fact I didn't have this problem the first week. Any ideas what is causing this? Same browser, no chrome new chrome addons, no new software (although I did install a game on steam) no browser updates or windows updates.

not sure if I should post this here but it didn't really meet the guidelines of the fantasy boards. Although I guess this isn't game or client related I'll just post this here.