If the value of “Additional Lines to Search for Regular Expressions” parameter is greater than 0, take the following piece of text for eg (t is a tab char).
1> If the cursor is in the first line, the regular expression pattern “[^d]rn” only matches the “rn” character at the end of the second and the third line. The replacement function fails in both positions.
2> If the cursor is in the second line, the pattern “[^d]rn” can match “ern”, and then clicking the “Find Next” button, it only matches “A” at the end of the third line and the replacement function doesn’t work here.
When “Additional Lines to Search for Regular Expressions”=0, it matches correctly.