Win10 cancels the PDF file by default with the Spartan browser open method

Win10 has a built-in reader application. This is a great way to view PDF files, but I don't know why PDF files are opened by default in Spartan browser. How to solve this problem?
Operation steps
First step, right click on the pdf file, select "ldquo; attribute" in the menu.

Step 2, in the pdf file properties dialog box, under the General tab, click on “Change” after the open method.

The third step, in the "How do you want to open this .pdf file from now on?" window, select "Reader”.

If you don't know where the Win10 reader app is or how the reader opens, you can click on the link to see it, so you don't have to open the reader from the file every time.