If i accessed to an existing script from a button of a layout, using theses steps : 1. "Button setup…" floating window 2. Script Button 3. "Edit…" pop menu item, i am then able to edit the target script, like adding or removing steps etc...
However, i am unable to disable a step using the [ / ] key : this key is opening Help Menu.
If i accessed the script from Script Workspace all is fine, even if i have open the script in a separate window. This could be related to the menu set which is not changed when you are accessing the script from a layout : it is still "Layout Mode menu set" and not "Script workspace menu set".
This issue surely have more larger scope than just "Disable step" vanishing.
Configuration tested :
FileMaker Pro Advanced 14.0.2
OS X 10.9.5
MacBook Pro 15"