## Feature Request: Improve Column Mode same as UltraEdit

Description

Feature Request: Improve Column Mode same as UltraEdit

Current NotepadNext supports basic rectangular selection by Alt + drag mouse, but lacks many practical column‑editing features that UltraEdit(UE) provides. For processing fixed‑width log / CSV / structured text, UE’s column‑mode is very convenient.

Describe the solution you'd like

P0 Must‑have：

1. Persistent toggle column‑block mode (shortcut like Alt+C in UE, menu entry in Edit menu, status‑bar indicator to show column‑mode is active)
2. Column insert sequential numbers (decimal/hex) in column selection
3. Column‑oriented operations: fill text into selected column block, delete whole‑column block
4. Column alignment: left‑align / right‑align / center for selected column block

P1 Nice‑to‑have:

1. Column sum for numeric values inside column selection
2. Column markers (vertical ruler line at specified column position)
3. Support find‑replace only within selected column block

Describe alternatives you've considered

Current Alt‑drag only gives temporary selection, no dedicated column operation menu. I have to switch back to UltraEdit for these tasks.

Additional context UltraEdit column‑mode doc reference: https://wiki.ultraedit.com/Column_mode My OS: macOS