It is a useful function of UltraEdit. I wish EmEditor can implement it soon.

A column marker is a thin vertical line that indicates the position of the column on the screen. If a column marker is specified to be at column 80, the marker is placed between the 80th column and the 81st column.

If this feature is enabled, columns to the right of the marker will scroll horizontally while columns to the left will not. While the horizontal scroll is in effect, any mouse selection or clicking of the primary mouse button within the fixed portion of the display will cause the horizontal scroll position to be reset allowing viewing and editing of the continuous columns.

When this item is checked (enabled) the columns to the left of the 1st column marker are fixed, and do not scroll horizontally while the columns to the right of the column marker will scroll as normal when the horizontal scroll bar is used or when the cursor is positioned to the right hand side of the window forcing a horizontal scroll.

Unlike EmEditor’s horizontal line and vertical line, the column marker is a fixed line.

BTW: Column Mode is another very powerful feature of UltraEdit. Is it possible to update EmEditor’s Box selection to a powerful “Box Edit mode” or “Column Edit mode”