The “Leading String” pop-up menu in the Process Select Window controls how a specific character string is compared against, or simply inserted at, the beginning of each line.
This string defaults to a single space, can be redefined by selecting the “Edit string…” item in the pop-up menu. Characters may be entered via the keyboard or clipboard, or in #ASCII format. This string is limited to 25 characters and may not contain CRs.
When stripping or replacing with a tab, the string is repeatedly compared against the start of the line until there is no match, so that a single space used as the string removes all leading spaces or replaces all leading spaces with a tab. Likewise, a single period serves for leader dots.
