Hi ,
I can able to disable the On Hold Button Under Maintain Group of Vendor Master using Event handler
[FormDataSourceEventHandler(formDataSourceStr(VendTable, VendTable), FormDataSourceEventType::Activated)]
public static void VendTable_OnActivated(FormDataSource sender, FormDataSourceEventArgs e)
{
#define.BUTTONNAME('VendorStatusApproval')
VendTable vendTable = sender.cursor();
FormRun element = sender.formRun();
FormControl Button = element.design(0).controlName(formControlStr(VendTable, OnHoldDropDialogButton));
Button.enabled(**condition**);
}

But How can I disable the Vendor Hold Dropdown Field I have tried to add this line of code
FormControl Button = element.design(0).controlName(formControlStr(VendOnHoldUpdate, OnHold));
But I am getting the runtime object error .

I have even tried Chain of command for the vendor hold field But it doesnt trigger anything
How Can I disable the vendor hold drop down?
[ExtensionOf(formDataSourceStr(VendTable,VendTable))]
final class VendTable_DS_Extension
{
public int active()
{
int ret = next active();
VendTable vendTable= this.cursor();
this.object(fieldNum(Vendtable, Blocked)).allowEdit(false);
return ret;
}
}