We are here to help you, mld.engraving. 

Let me share other steps that will let you show the list of all your sales tax that includes the inactive ones. 

Here's how: 

1. Select Taxes in the left menu then choose Sales Tax. 
2. On the upper-right corner, select the Sales tax settings link. 
3. Beside the Add agency button, click the Gear icon and check the Include inactive box. 
4. After, you can make the inactive sales tax to active and Edit it. 

I'm here to guide you if you have other questions.