It's
relatively simple... I'll try to give a quick explanation.
Each item has a number associated with it, which you can see when you select the item in the LD. For example, the coin is number 2.
I do it this way:
1. Place the item you want to disable. Make it the last item you place. Also, take a look at the number. For this case, we'll use the coin (number 2).
2. Get the code and paste it to Notepad or wherever you can manipulate it.
3. Look for the string of code that represents the item. If you made it the last item you placed, like I said, it will be by the end of the text. The text should end in something like this:
|2,209,719~1~1~My%20Level
The ~1~1~My%20Level part isn't part of the item's code, but it's what the code ends in.
The 2 at the beginning is what matters to us. That's the item's ID (I think I said that right). Now, what you do is you place a 0 right before that number, so it looks like this:
|02,209,719~1~1~My%20Level
Now take your edited code and paste it back into the Level Designer. That item is now disabled! It will look pretty, but can't be interacted with.
I think that if the item is from the second tab (enemies and other thingies) you add 50 to the number, and 100 if it's from the third tab (trees and other background stuff). However, if you make your item the last thing placed, you don't really need to learn that. You just modify the last thing the code has. That's why I do it the way I do it. ^_^
I hope you learned something from this, and I hope this makes up for me never making that sigbar I promised.
I can still make it if you want...