Hi @eddiedaco 

Below is the sample code for…..If we select one checkbox to deselect the other selected automatically… 

  protected virtual void SOOrder_Checkbox1_FieldUpdated(PXCache sender, PXFieldUpdatedEventArgs e)
        {
            SOOrder row = e.Row as SOOrder;
            if (row != null)
            {
                SOOrderExt rowExt = row.GetExtension<SOOrderExt>();
                if (rowExt.Checkbox1 == true)
                {
                    rowExt.Checkbox2 = false;
					rowExt.Checkbox3 = false;
					rowExt.Checkbox4 = false;
                }
            }
        }

        protected virtual void SOOrder_Checkbox2_FieldUpdated(PXCache sender, PXFieldUpdatedEventArgs e)
        {
            SOOrder row = e.Row as SOOrder;
            if (row != null)
            {
                SOOrderExt rowExt = row.GetExtension<SOOrderExt>();
                if (rowExt.Checkbox2 == true)
                {
                    rowExt.Checkbox1 = false;
					rowExt.Checkbox3 = false;
					rowExt.Checkbox4 = false;
                }
            }
        }
		protected virtual void SOOrder_Checkbox3_FieldUpdated(PXCache sender, PXFieldUpdatedEventArgs e)
        {
            SOOrder row = e.Row as SOOrder;
            if (row != null)
            {
                SOOrderExt rowExt = row.GetExtension<SOOrderExt>();
                if (rowExt.Checkbox3 == true)
                {
                    rowExt.Checkbox1 = false;
					rowExt.Checkbox2 = false;
					rowExt.Checkbox4 = false;
                }
            }
        }
		protected virtual void SOOrder_Checkbox4_FieldUpdated(PXCache sender, PXFieldUpdatedEventArgs e)
        {
            SOOrder row = e.Row as SOOrder;
            if (row != null)
            {
                SOOrderExt rowExt = row.GetExtension<SOOrderExt>();
                if (rowExt.Checkbox4 == true)
                {
                    rowExt.Checkbox1 = false;
					rowExt.Checkbox2 = false;
					rowExt.Checkbox3 = false;
                }
            }
        }

Thanks @Naveen B for the answer. I resolve the problem using the new event declaration.

    protected void _(Events.FieldUpdated<CEBidLeveling, CEBidLeveling.internalBudgetChecked> e)
    {
      var row = (CEBidLeveling)e.Row;
  
      if(row.InternalBudgetChecked==true)
      {
        row.Vendor_1Checked =false;
        row.Vendor_2Checked = false;
        row.Vendor_3Checked = false;
        row.Vendor_4Checked = false;
      }
    }

and set the commit changes property = true.

for some reason my acumatica version doesnt recognize the normal event declaration.