Workflow Foundation: Designer can't resolve a property

Question

I have a project that won't build due to an unresolved property. Need help to know where to look. I attached two screenshots

and :

So I don't get why VS can't resolve the properties on the designer surface while showing it in the object explorer.

I have a feeling that I'm missing something basic.

Appreciate any help or suggestions

Update:

Section from XAML causing the problem: Note that The assembly TBSM.Common.Entities contains the namespace TBSM.Common.Entities.Credentials which has the reference reported as missing. This still mystifies me

 xmlns:tcec="clr-namespace:TBSM.Common.Entities.Credentials;assembly=TBSM.Common.Entities"
 xmlns:tcfc="clr-namespace:TBSM.Common.Framework.Credentials;assembly=TBSM.Common.Framework"
 xmlns:this="clr-namespace:TBSM.Vision.Workflow.Primary"
 xmlns:ttwag="clr-namespace:TBSM.TBSMLIB.Workflows.Activities.General;assembly=TBSM.TBSMLIB.Workflows.Activities.General"
 xmlns:ttwal="clr-namespace:TBSM.TBSMLIB.Workflows.Activities.Logging;assembly=TBSM.TBSMLIB.Workflows.Activities.Logging"
 xmlns:ttwanc="clr-namespace:TBSM.TBSMLIB.Workflows.Activities.Network.Credentials;assembly=TBSM.TBSMLIB.Workflows.Activities.Network"
 xmlns:ttwance="clr-namespace:TBSM.TBSMLIB.Workflows.Activities.Network.Credentials.Enums;assembly=TBSM.TBSMLIB.Workflows.Activities.Network"
 xmlns:tvdr="clr-namespace:TBSM.Vision.Domain.RunTypes;assembly=TBSM.Vision.Domain"
 xmlns:tve="clr-namespace:TBSM.Vision.Entities;assembly=TBSM.Vision.Entities"
 xmlns:tves="clr-namespace:TBSM.Vision.Entities.Settings;assembly=TBSM.Vision.Entities"
 xmlns:tvew="clr-namespace:TBSM.Vision.Entities.Workflow;assembly=TBSM.Vision.Entities"
 xmlns:tvews="clr-namespace:TBSM.Vision.Entities.Workflow.Settings;assembly=TBSM.Vision.Entities"
 xmlns:tvwa="clr-namespace:TBSM.Vision.Workflows.Activities;assembly=TBSM.Vision.Workflows.Activities"
 xmlns:tvwag="clr-namespace:TBSM.Vision.Workflows.Activities.General;assembly=TBSM.Vision.Workflows.Activities"
 xmlns:tvwam="clr-namespace:TBSM.Vision.Workflows.Activities.Members;assembly=TBSM.Vision.Workflows.Activities"
 xmlns:tvwap="clr-namespace:TBSM.Vision.Workflows.Activities.Parsers;assembly=TBSM.Vision.Workflows.Activities"
 xmlns:tvwap1="clr-namespace:TBSM.Vision.Workflows.Activities.Parameters;assembly=TBSM.Vision.Workflows.Activities"
 xmlns:tvwaps="clr-namespace:TBSM.Vision.Workflows.Activities.Parameters.Shared;assembly=TBSM.Vision.Workflows.Activities"
 xmlns:tvwar="clr-namespace:TBSM.Vision.Workflows.Activities.Reporting;assembly=TBSM.Vision.Workflows.Activities"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <x:Members>
    <x:Property Name="PortfolioFeedCode" Type="InArgument(x:String)">
      <x:Property.Attributes>
        <RequiredArgumentAttribute />
      </x:Property.Attributes>
    </x:Property>
    <x:Property Name="RunTypes" Type="InArgument(x:String)">
      <x:Property.Attributes>
        <RequiredArgumentAttribute />
      </x:Property.Attributes>
    </x:Property>
    <x:Property Name="Credentials" Type="InArgument(scg:Dictionary(tcec:CredentialKey, tcec:TbsmCredential))">

New Screenshot showing other includes