Allow top function panel to scroll if too many buttons to fit
I noticed that when the right side function panel has more buttons than will fit on the screen that it is possible to scroll this panel up and down - video here - very nice hidden feature. On my phone I can only have a maximum of 5 buttons on the top panel. Instead of this limitation I suggest the top panel can if necessary scroll left & right to show all buttons, similar in operation to the right side panel. Don't place any limit to the number of buttons on either panel, just allow user to tap-drag scroll.