It is becoming difficult to collapse a node because sometimes it is not fully expanded, so you have to expand it first then press again to collapse which takes more time. Replace the expand/collapse button with a rectangle with two buttons. Each button has a different color (green for '+' & red for '-') and if one of the options is not available, grey it out.
It is becoming difficult to collapse a node because sometimes it is not fully expanded, so you have to expand it first then press again to collapse which takes more time. Replace the expand/collapse button with a rectangle with two buttons. Each button has a different color (green for '+' & red for '-') and if one of the options is not available, grey it out.