When right-clicking > View Details on a Variant number you may receive the following message  “The Product variants form can only be opened for a product master.”

Call Stack

    Data DictionaryTablesEcoResProductMasterMethodsgetProductMasterFromCaller   34
    ClassesEcoResProductVariantsCompanyHelpernewFromFormRun       18
    ClassesEcoResProductVariantsFormHelpernewFromFormRun             21
    FormsEcoResProductVariantsPerCompanyMethodsproductVariantsFormHelper 5
    FormsEcoResProductVariantsPerCompanyMethodsinit       3
    ClassesSysSetupFormRuninit                           5
    ClassesFormDataObjectjumpRef                                                                          
    ClassesFormStringControljumpRef                                                                       
    ClassesFormRunTask                                                                                    
    ClassesSysSetupFormRunTask                48
    ClassesFormStringControlContext                                                                       

Problem

The method Data DictionaryTablesEcoResProductMaster.getProductMasterFromCaller() handles EcoResDistinctProductVariant but not InventDimCombination.
Solution
Add the following code to Data DictionaryTablesEcoResProductMaster.getProductMasterFromCaller()
    //coming from the Go to Main Table
    if (_args.lookupTable() == tableNum(InventDimCombination))
    {
        ecoResDistinctProductVariantCaller = EcoResDistinctProductVariant::find(InventDimCombination::findVariantId(_args.lookupValue()).DistinctProductVariant);
        callerRecord = EcoResProductMaster::find(ecoResDistinctProductVariantCaller.ProductMaster);
    }