Great that you find it useful 
I hope I get you right:
In order to disable "use with" or in other words force use, you have to add the use extension to item's description. If you look at the item iEnvClose from the test room, you can see it there.
In order to enable "use with" you simply remove the extension, like in the item iKey.
This way you still have the "use" verb active. So single click on the item directly brings you to "use with" and using the verb directly uses the item. Although I can' really suggest this, as nobody would expect that click the verb does something different than simply clicking the item.
Now if you want to force use with you have to get rid of the extension and clear the function from the event "Interact inventory item".
That way, it's always "use with". No matter if you directly click or use the verb.
I hope that helps.
-----edit:
I've updated the manual and fixed a few bugs. Please enjoy v.1.2.1

I hope I get you right:
In order to disable "use with" or in other words force use, you have to add the use extension to item's description. If you look at the item iEnvClose from the test room, you can see it there.
In order to enable "use with" you simply remove the extension, like in the item iKey.
This way you still have the "use" verb active. So single click on the item directly brings you to "use with" and using the verb directly uses the item. Although I can' really suggest this, as nobody would expect that click the verb does something different than simply clicking the item.
Now if you want to force use with you have to get rid of the extension and clear the function from the event "Interact inventory item".
That way, it's always "use with". No matter if you directly click or use the verb.
I hope that helps.
-----edit:
I've updated the manual and fixed a few bugs. Please enjoy v.1.2.1
