Since I have multiple categories, what I'm aiming to do is hide the category selector when someone tries to add a new entry. The only way to add entries is to be in one of the categories, that way the category is automatically selected.
Mark69, I developed a script which can automatically select an item from the category list a while back for my own site. I will link you to it once I've found where I last used it. If this is what you are meaning of course - I am not sure however if it will work with the category box hidden essentially. I will look into it for you.
But as to your question, it is definitely possible with custom scripting.
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