Up/Down arrows stop working when scrolling tweets

I'm using the Seesmic Desktop Preview and have noticed a consistent problem related to use of the up/down arrows when scrolling through a list of tweets. The problem is that after about 5 up or down arrows, they stop working and will not work again until I click on the listof Tweets again.

It almost seems like there is some periodic process that it stealing focus from the scrollable tweet list forcing me to refocus on it to regain control.

If I could add something else in here: I would love to be able to use the spacebar for pagin down.