The size of firefox 'window changed when I use the Totem to listen mp3

[daixf]

Dear all,
 
       just now ,I have install the Totem to listen the mp3 in firefox 
online.

when I am using it,the window of firefox  will be changed so small ,It 
become
as small as the Totem, I think it is a terrible for me.

 Can anyone can tell me how I can configure my firefox ,so that the 
windows will not be change when I use the Totem in firefox.

thanks