Debugger freeze

Dear Sir or Madam,
I am writing to report a bug in pgadmin III 1.22.0 running on Windows 7 x64 connected to PostgreSQL 9.5.0 VC++ build 1800, 64 bit.
To reproduce the bug create this trivial function using SQL query editor. The example is in "playground" schema.

create function playground.dbg_test() returns void as
$$
declare
    i integer;
    t text;
begin
    for i in 1 .. 100 loop
        t := 'XYZ' || to_char(i, '999');
        raise notice 'Round %', t;
    end loop;
end;
$$ language plpgsql;

Right-click the function in Object browser then debug. Step a few times through the loop then take some time doing other things in pgadmin iii (browse data, run queries etc.) then return to the debug window and step again a few times. The debug window usually freezes (debug.png).
Two locks remain (server status.png). The server may be cleared by cancelling the query of the global listener (pid 7748 in the example) but then pgadmin windows  stop responding.

This is preventing me from using the debugger and I need it badly.

Thank you for the great job you are doing.
Sincerely, Stefan