diff --git a/src/gd_con.erl b/src/gd_con.erl
index 88b9e71..996b3fe 100644
--- a/src/gd_con.erl
+++ b/src/gd_con.erl
@@ -1349,11 +1349,14 @@ do_tic(MS, State = #s{timer = {T, _}}) ->
     T = erlang:send_after(MS, self(), tic),
     State#s{timer = {T, MS}}.
 
+handle_tic(State = #s{wallet = #wallet{poas = []}, timer = {T, MS}}) ->
+    ok = cancel_timer(T),
+    NewT = erlang:send_after(MS, self(), tic),
+    State#s{timer = {NewT, MS}};
 handle_tic(State = #s{wallet   = This = #wallet{poas = POAs, endpoint = Node},
                       timer    = {T, MS},
                       selected = Selected})
         when Selected > 0 ->
-    
     NewState =
         case ensure_hz_set(Node) of
             {ok, ChainID} ->
diff --git a/src/gd_v_devman.erl b/src/gd_v_devman.erl
index e44b868..731a7a2 100644
--- a/src/gd_v_devman.erl
+++ b/src/gd_v_devman.erl
@@ -344,6 +344,7 @@ clicked3(State = #s{frame = Frame, j = J}, Contract, Name = {FunName, FunType},
     KeyPicker = wxChoice:new(Dialog, ?wxID_ANY, [{choices, Keys}]),
     _ = wxStaticBoxSizer:add(KeySz, KeyPicker, zxw:flags(wide)),
     ok = wxChoice:setSelection(KeyPicker, Selected - 1),
+    ArgSz = call_arg_sizer(Dialog, J, FunSpec),
     {ParamSz, TTL_Tx, GasP_Tx, Gas_Tx, Amount_Tx} = call_param_sizer(Dialog, J),
     ButtSz = wxBoxSizer:new(?wxHORIZONTAL),
     Affirm = wxButton:new(Dialog, ?wxID_OK),
@@ -351,6 +352,7 @@ clicked3(State = #s{frame = Frame, j = J}, Contract, Name = {FunName, FunType},
     _ = wxBoxSizer:add(ButtSz, Affirm, zxw:flags(wide)),
     _ = wxBoxSizer:add(ButtSz, Cancel, zxw:flags(wide)),
     _ = wxSizer:add(Sizer, KeySz,   zxw:flags(wide)),
+    _ = wxSizer:add(Sizer, ArgSz,   zxw:flags(wide)),
     _ = wxSizer:add(Sizer, ParamSz, zxw:flags(wide)),
     _ = wxSizer:add(Sizer, ButtSz,  zxw:flags(wide)),
     ok = wxDialog:setSizer(Dialog, Sizer),
@@ -384,6 +386,8 @@ clicked3(State = #s{frame = Frame, j = J}, Contract, Name = {FunName, FunType},
         Error        -> handle_troubling(State, Error)
     end.
 
+call_arg_sizer(Dialog, J, FunSpec) ->
+
 call_param_sizer(Dialog, J) ->
     {ok, Height} = hz:top_height(),
     DefTTL = Height + 10000,
@@ -423,14 +427,15 @@ call_params(Controls) ->
 call_params([], A) ->
     {ok, lists:reverse(A)};
 call_params([{L, C} | T], A) ->
-    O =
+    R =
         try
             {ok, list_to_integer(wxTextCtrl:getValue(C))}
         catch
             error:badarg -> {error, {L, not_an_integer}}
         end,
-    case O of
-        {ok, N} -> call_params(T, [N | A]);
+    case R of
+        {ok, N} when N >= 0 -> call_params(T, [N | A]);
+        {ok, N} when N  < 0 -> {error, {L, neg_integer}};
         Error   -> Error
     end.