Stock on some locations is not allowed to use for creation of pick list proposals.
This includes:

• Can be lined up locations linked to a production line
• Input location of a production line
• The production line
• Special locations linked to a warehouse
• Moveable locations
• Locked locations (Cycle count)
• All locations linked to a WA location

There is a view that is used to get those locations: PMX_DISALLOWED_LOCATIONS_FOR_PICKING

This view used a table with cached data: PMX_CDLP
This table contains the following data:

• Can be lined up locations linked to a production line
• Input location of a production line
• The production line
• Special locations linked to a warehouse
• Moveable locations
• All locations linked to a WA location

The query that is used:

 SELECT "PMX_OSEL"."Code" FROM "PMX_OSEL" WHERE "PMX_OSEL"."TypeCode" IN (N'PRODLINE', N'MOVLOC')
 UNION  SELECT "PMX_OSPL"."InputLocationCode" FROM "PMX_OSPL" WHERE "PMX_OSPL"."InputLocationCode" IS NOT NULL
 UNION  SELECT "PMX_OSPL"."PickToLocationCode" FROM "PMX_OSPL" WHERE "PMX_OSPL"."PickToLocationCode" IS NOT NULL
 UNION  SELECT "PMX_CBLU"."CanBeLinedUpLocationCode" FROM "PMX_CBLU"
 UNION  SELECT "PMX_OSWH"."StorLocLogCar" FROM "PMX_OSWH" WHERE "PMX_OSWH"."StorLocLogCar" IS NOT NULL
 UNION  SELECT "PMX_OSWH"."StorLocRetItem" FROM "PMX_OSWH" WHERE "PMX_OSWH"."StorLocRetItem" IS NOT NULL
 UNION  SELECT "PMX_OSWH"."StorLocLostAndFound" FROM "PMX_OSWH" WHERE "PMX_OSWH"."StorLocLostAndFound" IS NOT NULL
 UNION  SELECT "PMX_OSWA"."InputLocationCode" FROM "PMX_OSWA" WHERE "PMX_OSWA"."InputLocationCode" IS NOT NULL
 UNION  SELECT "PMX_OSWA"."InputWithBoxLocationCode" FROM "PMX_OSWA" WHERE "PMX_OSWA"."InputWithBoxLocationCode" IS NOT NULL
 UNION  SELECT "PMX_OSWA"."OutputLocationCode" FROM "PMX_OSWA" WHERE "PMX_OSWA"."OutputLocationCode" IS NOT NULL
 UNION  SELECT "PMX_OSSL"."Code" FROM "PMX_OSSL" WHERE "PMX_OSSL"."BlockStockFromBeingUsedOnProposal" = N'Y'

The cached table is filled when the add-on or fat client is started.

The locked locations are retrieved when running the view, because this information can change a lot.