@Iņigo:Very much thanks.
And I didn't know well that there isn't enough room for more icons because I use it on landscape mode nearly all the time.
In fact, CoolDragon's attachment pictures just reminded me of the icons arrangement.
https://www.mobileread.com/forums/att...3&d=1276777279
It amazed me at the first time I saw it.
But I found it out now that the cycling icon isn't so inconvenient for me when I'm used to it
