The alt-f command toggles freezing/unfreezing dynamic notation rendering.

Pressing alt-f will toggle between freezing/unfreezing dynamic notation rendering. Normally any change in the text editor’s content will trigger a re-rendering of the graphical notation. For large files, this takes an increasingly longer and longer time with the current architecture. In order to speed up data entry in the text editing window, the notation can be frozen with the alt-f command.

While the notation generation is frozen, any changes made in the text editor will not trigger an update in the notation. After changes have been made, pressing alt-f will unfreeze the notation and it will be updated to match the current contents of the text editor.

When the notation is frozen, the background of the notation turns white. Unfreezing the notation will return the background color to off-white:

freezing and unfreezing notation.
Freezing and unfreezing notation while typing in the text editor.