Traditionally the KCML program editor has not allowed blank lines to be entered into a program. Instead blank lines were inserted after RETURN and GOTO automatically when formatting the program as an aid to readability. These automatic blank lines are artifacts of the editor and are not present in the source code of a program saved with SAVE or SAVE ASCII. When RETURN was pressed in the editor the current statement was parsed, a new blank line was opened up below the current line and the cursor went to the start of it. If no text was entered on the line then the editor collapsed out the blank line. Pressing RETURN at the start of a line had the same effect except the blank line was opened up above the current line. Pressing RETURN in the middle of a line splits the line.

The KCML6 has another mode of operation controlled by the value of $OPTION LIST byte 3. If this byte is HEX(01), the default value, then the workbench editor behaves as described above when RETURN is pressed. If set to HEX(00) however then it will behave in a way more consistent with other Windows text editors. Pressing RETURN in the middle of a line is unchanged. Pressing RETURN at the beginning or end of a line will still open up a blank line but if nothing is entered the line will persist. Pressing RETURN again will generate a second blank line. No automatic blank lines following GOTO and RETURN are generated in this mode and the programmer is responsible for all formatting. When a program is listed with LIST the blank line will show as a colon on its own. These blank lines are saved in the source of a program. They are not source or binary compatible with previous versions of KCML.