The game doesn't show up in full screen mode

When i started a game i wanted to browse the shop for starting items .. every time i clicked on the shop it pinged instead :D .. after a while i decided to open the shop from the place that shows my gold .. when i did that the game suddenly crashed and then opened up again in mini screen mode .. (Yep it's true on the upper hand side there was the - X buttons and even the full screen button was disabled) .. I can't describe it really - I don't know how actually .. I tried to reconnect alot of times but it didn't fix it ..

And one more thing .. one time i tried to reconnect and when the loading screen appeared and i minimized the game from the (-) button on the Upper right side of the screen (Which was in mini screen mode as i mentioned earlier) .. the game continued loading and then started but in the background .. the game screen didn't show up and it didn't appear in the tabs (Alt + Tab) but the sound of the game was still correctly displaying ..

I am using Lenovo z51 laptop with windows 8.1 operating system if these info would help ..

Oh yeah .. and sorry for my bad english :D