This is a free version of ACE - ASM Code Editor.
It supports only syntax highlighting with a complete text editing toolset.
You can place markers in code so you can quickly jump to saved positions.
It recognizes local variables in procedures excluding the ones from other procedures, variables defined by PUBLIC keyword and variables defined in data segments.

Keyboard shortcuts:

Ctrl+PgUp/PgDn - navigate cursor to previous/next SEGMENT, procedure or other block definition (you can also use these in combination with the Shift key to select whole or parts of code blocks)

Ctrl+Up/Down Arrows - Scroll up/down