I am listening the user select event in google chrome extension content script like this:

document.addEventListener(TransGlobal.MOUSE_UP, firstMouseUp);

export async function firstMouseUp(e: MouseEvent) {
  if (selection && selection.toString().trim().length > 0) {
    // do some select logic
  }
}

Now I am facing a problem that the firstMouseUp will trigger when select element and unselect element. when double click the webpage event then trigger the select event, it works fine. But I did not want to trigger the select when click the free area of the web, when click the free area of the web page, the selected element will be unselected, also trigger the firstMouseUp, that make me crazy, what should I do to recognize the select or unselect? I found some text the unselect will trigger, for example, this page https://stackoverflow.com/help/badges/2278/custodian?userid=16801334. when I select the Custodian and unselected, both will trigger. other text unselect did not trigger: