This extension allows to make cells read-only or frozen. It provides three buttons:

  • unlock
  • read-only
  • frozen

For code-cells:
read-only: it can be executed, but its input cannot be changed.
frozen: It cannot be either altered or executed.

For markdown-cells:
read-only: It’s input can be viewed by double-clicking on it, but cannot be changed.
frozen: Input cannot be viewed by double-clicking.

To change the state of a selected cell, press the corresponding button.

The individual cell’s state is stored in its metadata and is applied to the cell if the extension is loaded.


The read-only state is stored in the cell.metadata.editable attribute. Cells are editable by default. The frozen state is stored in the cell.metadata.run_control.frozenattribute.