Implementing caascading prompts using web elements

Question

I am implementing caascading prompts using web elements for two dropdowns PL and MPLl. If a value is selected
from PL corresponding values are selected from MPL.
I am using following code in sub report
1) shared stringvar PL;
if instr(PL, field1 + "|") = 0 then PL := PL + field1 + "|";
2) shared stringvar MPL;
if instr(MPL,"||" + field1) = 0 then MPL:= MPL + "||" + field1 + "|";
if instr(MPL, field2 + "|") = 0 then MPL:= MPL + field2 + "|";
3)
shared stringvar PL:= PL[1 to length(PL)-1];
shared stringvar MPL:= MPL[1 to length(MPL)-1]; MPL:= replace(MPL, "|||", "||");
I am using following code in Main report
1) whileprintingrecords;
shared stringvar MultiSelectfont;
shared stringvar PL;
WESelectCascade ("Product_Line", PL, "Product_Line|MPL", {?Product_Line}, "ALL", true, "4.25cm", MultiSelectfont, "", "");
2)whileprintingrecords;
shared stringvar MultiSelectfont;
shared stringvar MPL;
WESelectCascade ("MPL", MPL, "Product_Line|MPL", {?MPL}, "ALL", true, "4.25cm",MultiSelectfont, "", "");
PL has 3 values {ED,Motors, services} ED has 8 values for MPL, Motors has 2 values for  corresponding MPL and services has 2 values for corresponding MPL.  when ED is selected in PL dropdown it is giving 6 values in MPL drop down instead of 8 values.   when Motors is selected in PL dropdown it is giving 2 values in MPL drop down which is correct.   when Services is selected in PL dropdown it is giving 4 values in MPL drop down instead of 2 values.   2 values from services and 2 values from ED. i.e. First selection remaining 2 values are added to last selection i.e. services.
Any Ideas appreciated

Answer 1

what are the values of the 2 shared variables?
i.e. if you un-suppress the formulae in the subreport that generate the 2 shared variables, then copy and paste using the Further Markup Possibilities > Markup/Result > code tags (to the right of the Message)  so that we can see the entire code.
what could be happening is that there are duplicate values in the 2nd level...each value has to be unique. if they are not unique look into using the Ext (extended) cascading sets where a Display and a Value are used.