Hello,
With the last version (V1.2020.7) you have add the possibility to use a backward command within a while loop. it works, but if you want to continue the diagram, the loopback arrow touch the continuation one and therefore the diagram is confusing:
@startuml
start
while(a)is(b)
:do something;
backward:test;
endwhile
#FF8080:Confusing layout
The arrows look
to cross each other>
while(a)is(b)
:do something;
:test;
endwhile
#80FF80:Correct
arrow layout>
@enduml