@Jeng the black screen happens to me on occasion as well but in the browser I normally fix it by refreshing. and then waiting for it to fully load before trying again. You might also want to check and make sure you don't have any unneeded programs running in the background that tends to interfere as well from my experience.

@Harry13 there is currently no zoom function on the mini client. It could be the computer's resolution making everything too big to fit on the screen maybe try lowering it to see if that helps.