Also when selecting a group of filters space will disable / enable the selected group (which is all very well and good) left clicking will only disable / enable the one that was clicked regardless of how many are selected. I think the left mouse button should behave the same as space.
Also what do you think about separating the user sections from the subscription sections with some kind of heading ?

Notice I removed the top "Add Filter" option, I don't see the need for this, the button down the bottom works fine.