It's hard to pinpoint this one but you get some odd behaviour when filtering the list in some, not all, circumstances.
It seems that the keyboard input lags way behind the display sometimes, it is almost as if it is lagging behind, but will respond immediately as soon as the enter key is pressed.
This is on Linux x64 build btw. I'll try to capture some video if I can, its really intermittent though so may be difficult!