The selector is a string of characters used to identify objects on the screen. The selector is one of the properties of UI activities and has an XML format. All the activities in UiPath Studio related to graphical elements have the selector property.
Difference between Partial And Full Selectors:
Full Selectors: Which contains all the elements (HTML) needs to identify the element with the top level window(Which contains tags like html or wnd), generally top level window contains informations like URL and other important informations about website or an app.
Partial Selectors: Which is used inside containers, doesn’t contains information about the top-level window. Activities containing partial selectors are enclosed in a container Attach Browser or Attach Window that contains a full selector of the top-level window
Refer the following link for the better understanding: