Using the following:
this is 1
and here is the number 1
Open the ‘find in buffer’ pane (ctrl - f), click the ‘only in selection’ button, highlight the first line and replace 1 with 2.
Now highlight the second line, it comes back with no results for the number 1 until you type in something else and then retype the number 1.
edit: v0.123.0 on Win8.1