When trying to modify code in the editor, I am not able to and I see the word "Disabled".
Team Coding is turned on.
If Team Coding is enabled by accident, disable it.
If Team Coding is not enabled by accident, then you will need to check out the object's code that you are trying to modify.
You can disable Team Coding by...
For Toad v10.6 and under:
Select Utilities | Team Coding | Team Coding Status and click the Settings button. Uncheck the 'Enable Team Coding' option. You need to have the TC_Admin role granted to your user in order to disable Team Coding.
For Toad v11 and over...
Select Utilities | Team Coding | Configure Team Coding and uncheck the 'Enable Team Coding' option. You need to be a non-SYS adming user to disable Team Coding.