Default Problem double click Home button

Hi all,
I'm using device : HTC J one
And for ever i use rom : HTC 4.4.2 sense 6.0 beta for soku
I don't what happen , when i double click home button, my recent apps don't appear. Anyone can help me ? ? ?
And warning , i see build.prop for 4.4.2 sense 6 , the paragraph : "qemu.hw.mainkeys=1", but in 4.4.2 sense 5.5 i don't see it.