When the combinator is connected to a signal which is quickly changing (f.e a belt on-pulse) the gui display is very quickly shifting left & right because of the update of the gui in on_tick.
This makes it impossible to use the gui at that moment.
The code that updates the gui is :
local red, green = get_networks(com983,global.combinators983[unit_nr983].output)
for sig983,val983 in pairs(red) do
local cap = gui983.main_table.flow.add{type="label",name="red_"..sig983,caption=sig983.."= "..val983}
cap.style.font_color= {r=1,g=0.3,b=0.3}
end
for sig983,val983 in pairs(green) do
local cap = gui983.main_table.flow.add{type="label",name="green_"..sig983,caption=sig983.."= "..val983}
cap.style.font_color= {r=0.3,g=1,b=0.3}
end